What is constituent? What is constituent? Serving as part of a whole; component: a constituent element.Empowered to elect or designate.Authorized to make or amend a constitution: a constituent assembly.A constituent part; a component. See Synonyms at element.A resident of a district or member of a group represented by an elected official.One that authorizes another to act as a representative; a client.A structural unit, such as a verb, noun phrase, or clause, in a grammatical construction.