penetrate vs diffuse

penetrate is not an adjective while diffuse is an adjective.

Word	Noun	Adjective	Verb	Adverb
penetrate	No	No	Yes	No
diffuse	No	Yes	Yes	No

As verbs, diffuse is a hyponym of penetrate; that is, diffuse is a word with a more specific, narrower meaning than penetrate:

As verbs, penetrate and diffuse are synonyms defined as:

Other synonyms of penetrate include imbue, interpenetrate, permeate, pervade, riddle.

penetrate (adjective)	diffuse (adjective)
	(of light) transmitted from a broad light source or reflected
	spread out; not concentrated in one place
	lacking conciseness

penetrate (verb)	diffuse (verb)
come to understand	cause to become widely known
become clear or enter one's consciousness or emotions	spread or diffuse through
pass into or through, often by overcoming resistance	move outward
insert the penis into the vagina or anus of
spread or diffuse through
make one's way deeper into or through
enter a group or organization in order to spy on the members