Unable to express yourself clearly or fluently:
— Felt tongue-tied with embarrassment.

synonym: incoherent.

Roget 581: aphonous^†, dumb, mute; deafmute, deaf and dumb; mum; tongue-tied; breathless, tongueless, voiceless, speechless, wordless; mute as a fish, mute as a stockfish^†, mute as a mackerel; silent etc. (taciturn) 585; muzzled; inarticulate, inaudible.    croaking, raucous, hoarse, husky, dry, hollow, sepulchral, hoarse as a raven; rough.    ... show more