sleeper vs figure of speech

sleeper and figure of speech both are nouns.

Word	Noun	Adjective	Verb	Adverb
sleeper	Yes	No	No	No
figure of speech	Yes	No	No	No

sleeper (noun)	figure of speech (noun)
an unexpected hit	language used in a figurative or nonliteral sense
tropical fish that resembles a goby and rests quietly on the bottom in shallow water
a passenger car that has berths for sleeping
one of the cross braces that support the rails on a railway track
a piece of furniture that can be opened up into a bed
pajamas with feet; worn by children
a rester who is sleeping
an unexpected achiever of success
a spy or saboteur or terrorist planted in an enemy country who lives there as a law-abiding citizen until activated by a prearranged signal