driving vs rein in

driving is a noun but rein in is not a noun.

Word	Noun	Adjective	Verb	Adverb
driving	Yes	Yes	No	No
rein in	No	No	Yes	No

driving (noun)	rein in (noun)
the act of controlling and steering the movement of a vehicle or animal
hitting a golf ball off of a tee with a driver

driving (adjective)	rein in (adjective)
having the power of driving or impelling
acting with vigor

driving (verb)	rein in (verb)
	stop or slow up one's horse or oneself by or as if by pulling the reins
	stop or check by or as if by a pull at the reins
	control and direct with or as if by reins