darken vs dim

darken is not an adjective while dim is an adjective.

Word	Noun	Adjective	Verb	Adverb
darken	No	No	Yes	No
dim	No	Yes	Yes	No

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

Other hyponyms of darken include embrown, murk, dun, blind, bedim, benight, shade, shade off, shadow, cloud, overcast.

darken (adjective)	dim (adjective)
	made dim or less bright
	lacking in light; not bright or harsh
	offering little or no hope
	lacking clarity or distinctness
	slow to learn or understand; lacking intellectual acuity

darken (verb)	dim (verb)
become dark or darker	make dim or lusterless
make dark or darker	become dim or lusterless
tarnish or stain	make dim by comparison or conceal
	become vague or indistinct
	switch (a car's headlights) from a higher to a lower beam