fast one vs device

fast one and device both are nouns.

Word	Noun	Adjective	Verb	Adverb
fast one	Yes	No	No	No
device	Yes	No	No	No

As nouns, device is a hypernym of fast one; that is, device is a word with a broader meaning than fast one:

Other hypernyms of fast one include gimmick, twist.

fast one (noun)	device (noun)
a cunning or deceitful action or device	any clever maneuver
	an instrumentality invented for a particular purpose
	an emblematic design (especially in heraldry)
	any ornamental pattern or design (as in embroidery)
	something in an artistic work designed to achieve a particular effect