slowpoke vs stick-in-the-mud

slowpoke and stick-in-the-mud both are nouns.

Word	Noun	Adjective	Verb	Adverb
slowpoke	Yes	No	No	No
stick-in-the-mud	Yes	Yes	No	No

As nouns, slowpoke and stick-in-the-mud are synonyms defined as:

Other synonyms of slowpoke include plodder, slowcoach.

slowpoke (noun)	stick-in-the-mud (noun)
someone who moves slowly	someone who moves slowly

slowpoke (adjective)	stick-in-the-mud (adjective)
	(used pejoratively) out of fashion; old fashioned