gabfest n.

"talk much," 1786, probably via Scottish and northern England dialect from earlier sense "speak foolishly; talk indiscreetly" (late 14c.), from gabben "to scoff, jeer; mock (someone), ridicule; reproach (oneself)," also "to lie to" (late 13c.), from a Scandinavian source, such as Old Norse gabba "to mock, make fun of," and probably in part from Old French gaber "to mock, jest; brag, boast," which, too, is from Scandinavian. Ultimately perhaps imitative (compare gabble, which might have shaded the sense of this word). Gabber was Middle English for "liar, deceiver; mocker." Related: Gabbed; gabbing.

word-forming element in colloquial compounds (hen-fest, gabfest, etc.), from 1889, American English, borrowed from German Fest "festival," abstracted from Volksfest, etc., from Middle High German vëst, from Latin festum "festival or holiday," neuter of festus "of a feast" (see feast (n.)).