yack; yak
1. noun
1
voluble talk. Echoic of idle chatter US, 1952.
2
a joke US, 1951.
3
a telephone sales solicitor, either for a legitimate business or for a confidence swindle US, 1985.
4
a watch. Possibly derived from Welsh gypsy yãkengeri (a clock, literally 'a thing of the eyes'). Still current, in second spelling, among market traders UK, 1812
2. verb
1
to talk volubly and either idly or stupidly or both US, 1949.
2
to vomit US, 1992