rein in vs driving

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

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

rein in (noun)	driving (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

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

rein in (verb)	driving (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