mouthful

Etymology 1

From Middle English mouthful, mouth-full, mouthe full, equivalent to mouth + -ful. Compare Dutch mondvol (“mouthful”), German Mundvoll (“mouthful”), Danish mundfuld (“mouthful”), Swedish munfull (“mouthful”), Icelandic munnfylli (“mouthful”). Compare also West Frisian mûlfol (“mouthful”).

noun

1. The amount that will fit in a mouth.
   He swallowed a mouthful of sea water when he fell in.
2. (slang) Quite a bit.
   “Unquestionably his metabolism is unduly susceptible to stresses resulting from the interaction of external excitations,” he said, and Bobbie patted him on the shoulder in a maternal sort of way, a thing I wouldn't have cared to do myself though our relations were, as I have indicated, more cordial than they had been at one time, and told him he had said a mouthful. 1960, P. G. Wodehouse, Jeeves in the Offing, chapter VII
3. Something difficult to pronounce or say.
   “She sells sea shells” is a bit of a mouthful to say.
   “Yes, you may leave this little matter entirely to me, Mr Wooster.” “I wish you'd call me Bertie.” “Certainly, certainly.” “And might I call you Roderick?” “I shall be delighted.” “Or Roddy? Roderick's rather a mouthful.” “Whichever you prefer.” 1960, P. G. Wodehouse, Jeeves in the Offing, chapter X
   "Tony, I'm the executive director of S.H.I.E.L.D., the Strategic Homeland Intelligence, Enforcement, and Logistics Division," explained Fury. Tony nodded. […] "Want a tip? Fire your namer of things, because that's a mouthful." 2010, Alexander Irvine, Iron Man 2: The Junior Novel, page 77
4. A tirade of abusive language.
   to give someone a mouthful

Etymology 2

mouth + -ful.

adj

1. Bombastic or awkward.
   Once this happens to be the result, there is little reason for waxing over such mouthful phrases as 'grass-roots democracy', 'democratic decentralization' or 'panchayati raj'. 1977, Asok Kumar Mukhopadhyay, The Panchayat Administration in West Bengal
   The sufferers are regaled with such mouthful promises by every party on the eve of the successive elections and thereafter they continue to be shouted with unabated vigour by the party occupying the saddle while the problems are relegated to the limbo of time to find out their own solutions. 1980, The Economic Studies - Volume 21, page 7
   Angley then drifts into his hourful, mouthful extempore, accentuated with refrains of "cast the demon away with the power of the Lord." 1981, The Diliman Review - Volume 29, page 74
   ...how else to explain such mouthful menu offerings as plantain-coated mahi mahi with fufu and lily salad and boneless braised short ribs with Paraguayan chipaguasu? 1995, Susan Spano, Matthew Debord, Sherill Tippins, Frommer's Irreverent Guide: Manhattan and New York, page 59