Colloquial(a.) Pertaining to, or used in, conversation, esp. common and familiar conversation; conversational; hence, unstudied; informal; as, colloquial intercourse; colloquial phrases; a colloquial style.
Colloquialism(n.) A colloquial expression, not employed in formal discourse or writing.
Colloquialize(v. t.) To make colloquial and familiar; as, to colloquialize one's style of writing.
Colloquies(pl. ) of Colloquy
Words within colloquials