profusion vs overgrowth

profusion and overgrowth both are nouns.

Word	Noun	Adjective	Verb	Adverb
profusion	Yes	No	No	No
overgrowth	Yes	No	No	No

As nouns, overgrowth is a hyponym of profusion; that is, overgrowth is a word with a more specific, narrower meaning than profusion:

Other hyponyms of profusion include greenness, verdancy, verdure, wilderness.

profusion (noun)	overgrowth (noun)
the property of being extremely abundant	a profusion of growth on or over something else
	excessive size; usually caused by excessive secretion of growth hormone from the pituitary gland