slacker vs scrimshanker

slacker and scrimshanker both are nouns.

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

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

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

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

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