ill-fed vs underfed

ill-fed and underfed both are adjectives.

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

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

Other synonyms of ill-fed include undernourished.

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