His wit's as thick as Tewksbury mustard; there's more conceit in him than is in a mallet.
Shak.
4. A fanciful, odd, or extravagant notion; a quant fancy; an unnatural or affected conception; a witty thought or turn of expression; a fanciful device; a whim; a quip.
On his way to the gibbet, a freak took him in the head to go off with a conceit.
L'Estrange.
Some to conceit alone their works confine,
And glittering thoughts struck out at every line.
Pope.
Tasso is full of conceits . . . which are not only below the dignity of heroic verse but contrary to its nature.
Dryden.