snake vs snake in the grass

snake and snake in the grass both are nouns.

Word	Noun	Adjective	Verb	Adverb
snake	Yes	No	Yes	No
snake in the grass	Yes	No	No	No

As nouns, snake and snake in the grass are synonyms defined as:

snake (noun)	snake in the grass (noun)
limbless scaly elongate reptile; some are venomous	a deceitful or treacherous person
something long, thin, and flexible that resembles a snake
a long flexible steel coil for dislodging stoppages in curved pipes
a deceitful or treacherous person

snake (verb)	snake in the grass (verb)
move along a winding path
move smoothly and sinuously, like a snake
form a snake-like pattern