private eye vs shamus

private eye and shamus both are nouns.

Word	Noun	Adjective	Verb	Adverb
private eye	Yes	No	No	No
shamus	Yes	No	No	No

As nouns, private eye and shamus are synonyms defined as:

private eye and shamus: someone who can be employed as a detective to collect information and assist in criminal investigations

Other synonyms of private eye include operative, PI, private detective, private investigator, sherlock.

private eye (noun)	shamus (noun)
someone who can be employed as a detective to collect information and assist in criminal investigations	someone who can be employed as a detective to collect information and assist in criminal investigations