shirker vs scrimshanker

shirker and scrimshanker both are nouns.

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

As nouns, scrimshanker is a hyponym of shirker; that is, scrimshanker 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)
scrimshanker: a shirker

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

shirker (noun)	scrimshanker (noun)
a person who shirks his work or duty (especially one who tries to evade military service in wartime)	a shirker