French adjectives describe nouns in various ways and usually have to agree with them in gender and number.
An adjective is something like "a word that describes a noun." If asked to name some adjectives, you might come up with words like small, pretty, and blue - in other words, descriptive adjectives. But did you know that there are many other types of adjectives as well? 
One of the eight parts of speech, adjectives are a type of modifier. They serve the same purpose in French and English, but they are very different in two respects. A1 French Lessons and Practice - Beginning French • adjectives • agreement • lesson plans • word order
By definition, adjectives modify nouns. But more than 30 French adjectives can sometimes modify verbs instead, thus taking on the role and characteristics of adverbs, including the fact that they are invariable. adjectives • adverbs • agreement
There are six French adjective / pronoun pairs, where an adjective + noun can be replaced by a corresponding pronoun. adjectives • B1 French Lessons and Practice - Intermediate French • pronouns
When describing someone as capable of doing or determined to do something, a preposition is required between the adjective and verb. In French, the choice of preposition depends on the adjective that precedes it, not the verb that follows. 
Adverbs of manner express how the action of a verb occurs. In English, the vast majority of adverbs of manner end in -ly, whereas in French, they mostly end in -ment. They are created from adjectives. A2 French Lessons and Practice - Low-Intermediate French • adjectives • adverbs
Grammatical agreement is a vast topic - and one of the banes of French students. While in English we have a few pronouns and adjectives that indicate gender and number (e.g., he/him/his and she/her/hers), in French, agreement is found in 5 of the 8 parts of speech. adjectives • articles • nouns • pronouns
The three French verb constructions which include some form of être plus a past participle usually require grammatical agreement of the past participle with the subject. A2 French Lessons and Practice - Low-Intermediate French • adjectives • agreement
abbreviations • adjectives • informalities • nouns
When colors are used as adjectives, they usually need to agree with the nouns they modify in gender and number - but there are some notable exceptions. 
Ce, cette, cet, and ces are demonstrative adjectives, which are used to indicate a specific noun or nouns. In French, they must agree with the noun(s) in number and sometimes gender. A2 French Lessons and Practice - Low-Intermediate French • adjectives • demonstratives • quick tips
Determiners are a category of grammatical terms that includes articles, numbers, and non-qualifying adjectives. Unlike qualifying adjectives, determiners serve two functions: they introduce and modify nouns at the same time. adjectives • articles • B1 French Lessons and Practice - Intermediate French
French grammar is sometimes trumped by pronunciation, as in the case of euphonic adjectives. Because French does not like the hiatus created when a word ending with a vowel precedes a word that begins with a vowel or mute h, a few adjectives change their spelling—and thus their pronunciation—for purely euphonic reasons. A2 French Lessons and Practice - Low-Intermediate French • adjectives • spelling
To express admiration, surprise, contempt, or another strong feeling about a noun, you can use the exclamative adjective quel, meaning "what (a)." adjectives • B1 French Lessons and Practice - Intermediate French • exclamations
French has borrowed or adapted a number of adjectives from other languages, and they are always invariable. 
