yammer
[verb]
Synonyms: gripe, beef, bellyache, bitch, bleat, blow off, crab, fuss, squawk, yawp (or yaup), chat, babble, chatter, clack, gab, gabble, jaw, prattle, yak, yakety-yak

[TahlilGaran] English Synonym Dictionary ▲

yam‧mer /ˈjæmə $ -ər/ (also yammer on) verb [intransitive]
[Date: 1400-1500; Origin: yomer 'to talk quietly, be sad' (12-15 centuries), from Old English geomrian]
informal to talk continuously in a way that is annoying:
a crowd of yammering aunts and cousins

[TahlilGaran] Dictionary of Contemporary English ▲