Etymology: < Irish pus lip, mouth, now also ‘pout’ (mid 16th cent. or earlier in derogatory use; 14th cent. in pusach having prominent lips), variant of bus, of uncertain origin (apparently related to Gaulish bussu-, probably ‘lip’, attested only in names and derivatives).
Irish English and slang (chiefly U.S.).
1. A person's face or mouth.
1844 Amer. Turf Reg. June 334 He [sc. an Irish fisherman] pointed to where a splendid fish rose and threw himself in sporting style. ‘Be quick, sir, or dat lad will run ahead af you don't put de hook in his puss.’