gumshoe vs investigator

gumshoe and investigator both are nouns.

Word	Noun	Adjective	Verb	Adverb
gumshoe	Yes	No	No	No
investigator	Yes	No	No	No

As nouns, investigator is a hypernym of gumshoe; that is, investigator is a word with a broader meaning than gumshoe:

Other hypernyms of gumshoe include detective, police detective, tec.

gumshoe (noun)	investigator (noun)
a waterproof overshoe that protects shoes from water or snow	someone who investigates
someone who is a detective	a scientist who devotes himself to doing research
	a police officer who investigates crimes