The Adjective
The French philosopher Voltaire once said the adjective is the enemy of the noun because it describes the noun only from the speaker’s perspective. It is a subjective view which can be misleading. Thus the Adjective can be seen just as an ornamental ivy that stifles the substantive tree. The evaluative, descriptive or emotional characteristics are the primary function of an adjective. Sometimes this type of distinction between evaluative and non-evaluative can also be made between two similar adjectives:
an economic policy means a policy for managing the economy, whereas
an economical person means a person who is clever at using money or even stingy:
The Scots are said to be economical.
A washing machine can be economical if it doesn't waste too much water which is of course environment friendly.

1. An adjective needs to be specified:
The word adjective is ambiguous because it can an attribute or a predicate. Most adjectives can be used attributively and predicatively. However, a few adjectives either cannot be used attributively or if used attributively change their meaning:
a. An attribute (a beautiful house)
b. A predicate (the house is beautiful)

The most popular adjectives which cannot be used both ways are: sick and ill:
a. She is sick/ill (used predicatively) BE and AmE difference being considered.
b. A sick man (used attributively)
c. An ill women (ill cannot be used attributively unless you change the meaning to bad something like: ill-manners

Another adjective is asleep. It cannot be used attributively either:
She is asleep but NOT an asleep girl

2. Some verbs take adjectives (predicates) not adverbs. They are called link(ing) or copular verbs.
See link(ing) verbs.

3. Past and present participles used as adjectives:
an interesting book (present participle)
a well-dressed man (past participle)

Please note there is a difference in meaning depending upon the preposition that follows the past participle "made":
A cake is made from milk (you don’t see milk in it)
A table is made of wood (you see wood).
A car is made in Germany (place of production)

4. The adjectival order:
Quality (beautiful) – size/age/shape (long, old) – color (brown) – origin (French) – made of (metal) – Type/usage (half moon) – noun (car, hair, glasses): beautiful old brown French metal half moon spectacles

However, it is not recommendable or convenient to have a long list of adjectives before a noun. Commas are not always necessary: she has long wavy brown hair – He has short spiky hair.: beautiful old brown French metal half moon spectacles
Old English silver mirror (age-origin-made of-noun)
Swedish wooden salad bowl (origin-made of-noun)

5. -ic and ical adjectives
The diachronic track, as often, is the key but is a very complex key. Some of the pairs have no distinguishable difference, as is the case with geographic / geographical; electric shock vs electrical shock . But some of the pairs are distinct: a historical record (one of the many records that have to do with history) isn't the same as a historic record such as the Magna Carta - a record that has particular significance in the context of history.

It seems quite possible that typesetters had a similarly cavalier attitude to -ic/-ical - they just stuck in an extra syllable if they wanted to pad out a line of type. And this applied not only to -ic/ical; physic (an archaic word referring to various aspects of medicine, which unlike 'public' has only the -ical form in current English) was sometimes spelt with -ic, sometimes -ick, and sometimes -icke.

The situation is unavoidably unclear. There are four possibilities:
a pair with the same meaning
a pair with distinct meanings
a 'pair' with only an -ic form
a 'pair' with only an -ical form.

There is no way of predicting which ones were 'chosen' by usage. And sometimes, even when there is a distinction, a quotation uses the 'wrong' form - simply because at the time of the quotation there was no such distinction. Compare the following:
Electric vs. electrical as an example:

An electric car (Not *electrical car)
Electrical engineering (Not *electric engineering)
An electric current (Not *electrical current)
An electric shock (Not *electrical shock)
Electrical equipment (Not *electric equipment)
Electrical components (Not *electric components)
The principle of economy can't be a satisfying explanation= the longer the noun (affixation), the shorter the adjective. The chosen examples are obvious.
Some searchers believed that -ic adjectives were chosen according to the essential link between noun and adjective:
Electric shock: the shock is no more than electricity. Here, the adjective is almost a noun. Electrical equipment or components: these things deal with electricity but are not essentially electricity it is peripheral.
In addition to semantic factors phonological and stress factors can play a role in addition to iconicity. The -ical ones seems having a faint tendency of being more abstract than the -ic ones.

The following text is a quote from:
-ic vs. -ical endings

Could you please explain the difference between historic and historical?
Adriana Guerrini
English has a number of parallel adjectives with -ic and -ical endings. They are similar in their forms and origins but somewhat different in their meanings and uses. Here are some pairs with their differences.
1. historic/historical:
Historic means unique, important in history, famous, something that happened for the first time. It also implies that the event itself made history:
The first trip to the moon was a historic event. (Some people might say AN historic event.)
Historical usually refers to history in general; it means that the event was part of a long story about the past:
"War and Peace" is a historical novel (a novel based on real events in history).
Napoleon's historical importance is enormous (his importance in the history of Europe).
2. economic/economical:
Economic refers to the area of financial activities:
Spending by consumers is one indicator of economic stability.
Economical means good value, inexpensive, not wasteful:
Buying a kilo of oranges is usually more economical than paying the price for each orange.
3. comic/comical:
Comic refers to comedy or humor in phrases like comic book, comic strip (newspaper cartoon), or comic actor. It can describe a type, like something or someone that makes you laugh, as in a comedy; it's intended to make you laugh.
He was often described as a brilliant comic actor, but Alec Guinness actually played many serious roles, too.
Comical (somewhat formal in use) means humorous, funny, amusing; something that makes you want to laugh because it strikes you as funny or silly at the moment, not necessarily because it was intended to.
The dog had a comical face.

The lawyer's outrageous defense of his client was so far-fetched that it was comical.
4. classic/classical:
Classic means memorable, an outstanding model or example of a class. The representation is good all by itself, and does not have distracting or trendy features:
The Ford Model T is a classic car.
Classical refers to a historically important form in music, art, or architecture based on ancient Roman or Greek models:
Beethoven composed symphonies in the classical period.
5. electric/electrical:
Electric means operated by electricity (and is sometimes used interchangeably with electrical).
My grandmother didn't have an electric washing machine; the one she had was operated manually.
Electric also means very vibrant, giving a pleasant shock:
The actor's performance was electric.
Electrical (used less often) refers to a circuit of electricity:
The storm damaged the electrical connection to my computer.
6. politic/political:
Politic means tactful, shrewd, clever; acting in one's own interest in an group or community:
Leaving the business was the only politic thing he could do after his mistake.
Political refers to the politics of running a government:
There are two major political parties in the United States.
7. problematic/problematical:
Problematic is preferred more than problematical although they are both used in the same way with the same meaning of puzzling, difficult to solve, uncertain:
The scientist's interpretation of the research data was problematic.
Because parallel pairs of adjectives like these are often problematical, it is helpful for students to have a good dictionary.
Barbara Matthies