subs. (colloquial).Conceit, bombast; properly a species of dropsy in which the belly is stretched tight like a drum.
1610. JOSEPH HALL, A Short Answer, etc., Preface. In the first leaf of my Defence, I foretold you so much; as finding nothing in that swollen bulk, but a meer unsound TYMPANY, instead of a truly solid conception.
TWO-LEGGED TYMPANY, subs. phr. (old).A baby; spec. a bastard: see supra. Hence TO BE CURED OF A TYMPANY WITH TWO HEELS = to be brought to bed; cf. a dropsy that will drop into the lap.