Homophone in French
leur and leurs

Difference between leurs and leurs

In a general way, leur, personal invariable pronoun, is invariable in front of a verb. If lui replaces leur then it is invariable.

Il leur reste un dernier espoir.
==> Il lui reste un dernier espoir.

But leur can also be a possessive adjective. In this case, it has the plural mark in front of a plural name : leurs.

Leur table est belle.
Leurs chaises sont jaunes.

Leur can also be a name in expression "le leur" which means "his/hers" or "theirs". There is also "être des leurs" to indicate a group or family integration.

Le voisin a aussi un chat mais le leur est gris.
Il est des leurs.