Understanding Irregular Adjectives
French irregular adjectives don't follow the standard agreement patterns. They have unique forms that must be memorized, and some have special forms before vowel sounds.
These adjectives are among the most commonly used in French, making them essential to master.
Many irregular adjectives also have special masculine forms used before words beginning with vowels or silent 'h'.
Examples
un beau garçon (a handsome boy)
un bel homme (a handsome man - before vowel)
une belle femme (a beautiful woman)
de beaux enfants (beautiful children)
BEAU (Beautiful/Handsome)
Beau is one of the most important irregular adjectives with five different forms:
All Forms of BEAU
Complete conjugation of beau:
BEAU Forms
| Pronoun | Conjugation | English |
|---|---|---|
| beau | masculine singular | un beau livre (a beautiful book) |
| bel | masculine before vowel | un bel homme (a handsome man) |
| belle | feminine singular | une belle femme (a beautiful woman) |
| beaux | masculine plural | de beaux livres (beautiful books) |
| belles | feminine plural | de belles femmes (beautiful women) |
When to Use BEL
Use "bel" before masculine words starting with vowels or silent h:
un bel ami (a handsome friend)
un bel hôtel (a beautiful hotel)
un bel appartement (a beautiful apartment)
un bel été (a beautiful summer)
NOUVEAU (New)
Nouveau follows the same pattern as beau with five forms:
All Forms of NOUVEAU
Complete conjugation of nouveau:
NOUVEAU Forms
| Pronoun | Conjugation | English |
|---|---|---|
| nouveau | masculine singular | un nouveau livre (a new book) |
| nouvel | masculine before vowel | un nouvel ami (a new friend) |
| nouvelle | feminine singular | une nouvelle voiture (a new car) |
| nouveaux | masculine plural | de nouveaux livres (new books) |
| nouvelles | feminine plural | de nouvelles voitures (new cars) |
NOUVEL Usage
Use "nouvel" before masculine words starting with vowels or silent h:
un nouvel ordinateur (a new computer)
un nouvel hôpital (a new hospital)
un nouvel étudiant (a new student)
un nouvel an (a new year)
VIEUX (Old)
Vieux also has five forms following the same pattern:
All Forms of VIEUX
Complete conjugation of vieux:
VIEUX Forms
| Pronoun | Conjugation | English |
|---|---|---|
| vieux | masculine singular | un vieux livre (an old book) |
| vieil | masculine before vowel | un vieil homme (an old man) |
| vieille | feminine singular | une vieille dame (an old lady) |
| vieux | masculine plural | de vieux livres (old books) |
| vieilles | feminine plural | de vieilles dames (old ladies) |
VIEIL Usage
Use "vieil" before masculine words starting with vowels or silent h:
un vieil ami (an old friend)
un vieil hôtel (an old hotel)
un vieil arbre (an old tree)
un vieil homme (an old man)
Other Common Irregular Adjectives
Several other adjectives have irregular patterns:
BLANC (White)
Blanc changes -c to -che for feminine:
BLANC Forms
| Pronoun | Conjugation | English |
|---|---|---|
| blanc | masculine singular | un chat blanc (a white cat) |
| blanche | feminine singular | une chatte blanche (a white female cat) |
| blancs | masculine plural | des chats blancs (white cats) |
| blanches | feminine plural | des chattes blanches (white female cats) |
LONG (Long)
Long adds -ue for feminine:
un long voyage (a long trip)
une longue histoire (a long story)
de longs voyages (long trips)
de longues histoires (long stories)
FOU (Crazy/Mad)
Fou has completely irregular forms:
FOU Forms
| Pronoun | Conjugation | English |
|---|---|---|
| fou | masculine singular | un homme fou (a crazy man) |
| folle | feminine singular | une femme folle (a crazy woman) |
| fous | masculine plural | des hommes fous (crazy men) |
| folles | feminine plural | des femmes folles (crazy women) |
Double Consonant Patterns
Some adjectives double their final consonant before adding -e for feminine:
BON (Good)
Bon doubles the n:
BON Forms
| Pronoun | Conjugation | English |
|---|---|---|
| bon | masculine singular | un bon livre (a good book) |
| bonne | feminine singular | une bonne idée (a good idea) |
| bons | masculine plural | de bons livres (good books) |
| bonnes | feminine plural | de bonnes idées (good ideas) |
GROS (Big/Fat)
Gros doubles the s:
un gros chat (a fat cat)
une grosse chatte (a fat female cat)
de gros problèmes (big problems)
de grosses difficultés (big difficulties)
GENTIL (Nice/Kind)
Gentil doubles the l:
un gentil garçon (a nice boy)
une gentille fille (a nice girl)
-EUX → -EUSE Pattern
Adjectives ending in -eux change to -euse for feminine:
Common -EUX Adjectives
These adjectives follow the -eux → -euse pattern:
-EUX → -EUSE Pattern
| Pronoun | Conjugation | English |
|---|---|---|
| heureux/heureuse | happy | Il est heureux. Elle est heureuse. |
| sérieux/sérieuse | serious | Un homme sérieux. Une femme sérieuse. |
| dangereux/dangereuse | dangerous | Un sport dangereux. Une route dangereuse. |
| nerveux/nerveuse | nervous | Un chat nerveux. Une chatte nerveuse. |
Plural Forms
Masculine plural stays -eux, feminine plural becomes -euses:
des hommes heureux (happy men)
des femmes heureuses (happy women)
des étudiants sérieux (serious students)
des étudiantes sérieuses (serious female students)
Memory Tips for Irregular Adjectives
Strategies for remembering irregular adjective forms:
1. Group similar patterns: beau/nouveau/vieux all follow the same pattern
2. Practice with common nouns: use frequent noun-adjective combinations
3. Listen for pronunciation: many irregular forms sound different
4. Learn in context: memorize complete phrases rather than isolated forms
Examples
Pattern group: un bel homme, un nouvel ami, un vieil arbre
All use special forms before vowels
Common phrases: une bonne idée, une longue histoire, une grosse voiture
Learn adjectives with typical nouns
Common Irregular Adjective Mistakes
Here are frequent errors students make with irregular adjectives:
1. Wrong special forms: Using beau instead of bel before vowels
2. Feminine formation: Using regular patterns for irregular adjectives
3. Plural confusion: Wrong plural forms for irregular adjectives
4. Pattern mixing: Confusing different irregular patterns
Examples
❌ un beau homme → ✅ un bel homme
Wrong: must use special form before vowel
❌ une blanque voiture → ✅ une blanche voiture
Wrong: blanc becomes blanche, not blanque
❌ des beaus livres → ✅ de beaux livres
Wrong: irregular plural is beaux
❌ une heureuxe femme → ✅ une femme heureuse
Wrong: -eux becomes -euse, not -euxe