French adjectives do two things English adjectives never do: they agree with the noun they describe (changing form for gender and number), and most of the time they go after the noun instead of before it.
1. Agreement: matching gender and number
In writing, the regular pattern is: add -e for the feminine, add -s for the plural (-es for feminine plural).
| un sac vert | a green bag (masc. sing.) |
| une robe verte | a green dress (fem. sing.) |
| des sacs verts | green bags (masc. pl.) |
| des robes vertes | green dresses (fem. pl.) |
Two shortcuts: an adjective already ending in -e in the masculine doesn't change for the feminine (un homme jeune / une femme jeune). And one already ending in -s or -x doesn't change in the masculine plural (un prix bas → des prix bas).
2. Irregular feminine forms
Some common adjectives don't just add -e; the ending changes in a predictable but irregular way.
| beau → belle | beautiful, handsome |
| nouveau → nouvelle | new |
| vieux → vieille | old |
| blanc → blanche | white |
| long → longue | long |
| bon → bonne | good |
| gentil → gentille | nice, kind |
3. Position: most adjectives go after the noun
| une voiture rouge | a red car |
| un film intéressant | an interesting movie |
| un pays magnifique | a magnificent country |
4. But some short, common adjectives go before the noun
A small group of everyday adjectives, mostly about beauty, age, goodness, and size, come before the noun instead.
| grand / petit | big/tall / small |
| jeune / vieux | young / old |
| beau / joli | beautiful / pretty |
| bon / mauvais | good / bad |
| nouveau | new |
| gros / long | big/fat / long |
| même / autre | same / other |
| premier | first |
Before a vowel sound: beau, nouveau, and vieux get a special masculine singular form when the next word starts with a vowel sound: bel, nouvel, vieil. un bel homme, un nouvel ami, un vieil ami.
5. Watch out: a few adjectives change meaning with position
| un grand homme | a great man |
| un homme grand | a tall man |
| un ancien professeur | a former teacher |
| un bâtiment ancien | an old/ancient building |
| ma propre chambre | my own room |
| une chambre propre | a clean room |
| ce pauvre homme | this poor (unfortunate) man |
| un homme pauvre | a poor (penniless) man |