four-flusher vs slicker

four-flusher and slicker both are nouns.

Word	Noun	Adjective	Verb	Adverb
four-flusher	Yes	No	No	No
slicker	Yes	No	No	No

As nouns, slicker is a hypernym of four-flusher; that is, slicker is a word with a broader meaning than four-flusher:

Other hypernyms of four-flusher include beguiler, cheat, cheater, deceiver, trickster.

four-flusher (noun)	slicker (noun)
a person who tries to bluff other people	a macintosh made from cotton fabric treated with oil and pigment to make it waterproof
	someone who leads you to believe something that is not true
	a person with good manners and stylish clothing