Leaven

n.	1.	Any substance that produces, or is designed to produce, fermentation, as in dough or liquids; esp., a portion of fermenting dough, which, mixed with a larger quantity of dough, produces a general change in the mass, and renders it light; yeast; barm.
	2.	Anything which makes a general assimilating (especially a corrupting) change in the mass. Beware of the leaven of the Pharisees, which is hypocrisy. - Luke xii. 1.
v. t.	1.	To make light by the action of leaven; to cause to ferment. [imp. & p. p. Leavened ; p. pr. & vb. n. Leavening .] A little leaven leaveneth the whole lump. - 1 Cor. v. 6.
	2.	To imbue; to infect; to vitiate. With these and the like deceivable doctrines, he leavens also his prayer. - Milton.

Noun	1.	leaven - a substance used to produce fermentation in dough or a liquid Synonyms: leavening
	2.	leaven - an influence that works subtly to lighten or modify something; "his sermons benefited from a leavening of humor" Synonyms: leavening
Verb	1.	leaven - cause to puff up with a leaven; "unleavened bread" Synonyms: prove, raise

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