YAK

I. noun (plural ~s; also ~) Etymology: Tibetan (Lhasa dialect) yaʔ (spelled gyag Date: 1795 a large long-haired wild or domesticated ox ( Bos grunniens syn. B. mutus ) of Tibet and adjacent elevated parts of central Asia, see: yuk III. intransitive verb also yack (~ked; also yacked; ~king; also yacking) Etymology: probably imitative Date: 1949 to talk persistently ; chatter , IV. noun also yack Date: 1950 persistent or voluble talk