leaven vs leavening

leaven and leavening both are nouns.

Word	Noun	Adjective	Verb	Adverb
leaven	Yes	No	Yes	No
leavening	Yes	No	No	No

As nouns, leaven and leavening are synonyms defined as:

leaven and leavening: an influence that works subtly to lighten or modify something

As nouns, leaven and leavening are synonyms defined as:

leaven and leavening: a substance used to produce fermentation in dough or a liquid

leaven (noun)	leavening (noun)
an influence that works subtly to lighten or modify something	an influence that works subtly to lighten or modify something
a substance used to produce fermentation in dough or a liquid	a substance used to produce fermentation in dough or a liquid

leaven (verb)	leavening (verb)
cause to puff up with a leaven