Nouns:
* Agent/Doer: accountant, assistant, consultant, contestant, defendant, informant, inhabitant, occupant, president, servant, student, tenant
* Place/Location: continent, inhabitant, restaurant, antecedent
Adjectives:
* Having the quality of: constant, distant, elegant, important, relevant, significant, transparent, vigilant, tolerant
Other:
* Verbs: combatant (participle of combat), habitant (participle of inhabit)
* Miscellaneous: instant, variant, mutant
These are just a few examples; there are many other words that end with "-ant."
Do you have a specific type of word in mind, or are you looking for a list of all words ending in "-ant"?