stop vs rein in

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

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

As verbs, rein in is a hyponym of stop; that is, rein in is a word with a more specific, narrower meaning than stop:

stop: come to a halt, stop moving
rein in: stop or slow up one's horse or oneself by or as if by pulling the reins

Other hyponyms of stop include go off, pull up short, check, check, check, rein, conk, stall, stall, draw up, haul up, pull up, brake, settle.

As verbs, rein in is a hyponym of stop; that is, rein in is a word with a more specific, narrower meaning than stop:

Other hyponyms of stop include check, rein, arrest, halt, hold, bring up, cut, flag down, stall, stall, draw up, pull up, brake.

stop (noun)	rein in (noun)
the act of stopping something
a brief stay in the course of a journey
a restraint that checks the motion of something
an obstruction in a pipe or tube
a mechanical device in a camera that controls size of aperture of the lens
(music) a knob on an organ that is pulled to change the sound quality from the organ pipes
a consonant produced by stopping the flow of air at some point and suddenly releasing it
a punctuation mark (.) placed at the end of a declarative sentence to indicate a full stop or after abbreviations
the event of something ending
a spot where something halts or pauses
the state of inactivity following an interruption

stop (verb)	rein in (verb)
prevent completion	stop or slow up one's horse or oneself by or as if by pulling the reins
stop and wait, as if awaiting further instructions or developments	stop or check by or as if by a pull at the reins
hold back, as of a danger or an enemy; check the expansion or influence of	control and direct with or as if by reins
seize on its way
render unsuitable for passage
come to a halt, stop moving
cause to end
interrupt a trip
stop from happening or developing
put an end to a state or an activity
have an end, in a temporal, spatial, or quantitative sense; either spatial or metaphorical