shirker vs skulker

shirker and skulker both are nouns.

Word	Noun	Adjective	Verb	Adverb
shirker	Yes	No	No	No
skulker	Yes	No	No	No

As nouns, skulker is a hyponym of shirker; that is, skulker is a word with a more specific, narrower meaning than shirker:

shirker: a person who shirks his work or duty (especially one who tries to evade military service in wartime)
skulker: someone shirking their duty by feigning illness or incapacity

Other hyponyms of shirker include goldbrick, malingerer, shammer, scrimshanker.

shirker (noun)	skulker (noun)
a person who shirks his work or duty (especially one who tries to evade military service in wartime)	someone waiting in concealment
	someone shirking their duty by feigning illness or incapacity