We usually add the unpronounced -s in the plural:
bon - bons
bonne - bonnes
petit - petits
petite - petites
If the noun ends in the singular in -s, -z, -x, we do not add any ending:
épais - épais
roux - roux
Special cases:
| singular | plural | examples |
| -al | - aux | amical - amicaux
national - nationaux exceptions (they have -als in plural): bancal - bancals similarly: banal, naval, fatal, final, glacial, jovial, pascal, austral |
| -eau | -eaux | beau – beaux
nouveau – nouveaux |
| -eu | differently | hébreu – hébreux
bleu – bleus |