underfed vs ill-fed

underfed and ill-fed both are adjectives.

Word	Noun	Adjective	Verb	Adverb
underfed	No	Yes	No	No
ill-fed	No	Yes	No	No

As adjectives, underfed and ill-fed are synonyms defined as:

Other synonyms of underfed include undernourished.

underfed (adjective)	ill-fed (adjective)
not getting adequate food	not getting adequate food