diffuse vs circulate

diffuse is an adjective but circulate is not an adjective.

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

As verbs, diffuse and circulate are synonyms defined as:

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

diffuse (verb)	circulate (verb)
cause to become widely known	cause to become widely known
spread or diffuse through	become widely known and passed on
move outward	move around freely from person to person or from place to place
	move through a space, circuit or system, returning to the starting point
	cause to be distributed
	cause to move in a circuit or system