readily fluent, often thoughtlessly, superficially, or insincerely so

a glib talker; glib answers.

easy or unconstrained, as actions or manners.

Archaic . agile; spry.

adjective

inarticulate , quiet , stuttering , tongue-tied , uncommunicative

adjective

artful , articulate , easy , eloquent , facile , fast-talking , flip , fluent , garrulous , hot-air , insincere , loquacious , plausible , quick , ready , silver-tongued * , slippery * , smooth operator , smooth-spoken * , smooth-tongued , suave , talkative , urbane , vocal , vocative , voluble , slick