onomatopoeian adjective 1noun 1forms 3 adjective1 •(no longer used) Of or pertaining to onomatopoeia.Hangs is a false word, — a Northern corruption of the negro dialect yang, — an onomatopoeian word, representing the "far heard clang" of the wild goose. — 1867 noun1 •(no longer used) A word formed by onomatopoeia.To slump; to slip, or fall plum down into any dirty, or wet place. It seems to he a word made per onomatopoeian from the sound. — 1818 formsonomatopoeians · more onomatopoeian · most onomatopoeian