constrain vs throttle

constrain is not a noun while throttle is a noun.

Word	Noun	Adjective	Verb	Adverb
constrain	No	No	Yes	No
throttle	Yes	No	Yes	No

As verbs, throttle is a hypernym of constrain; that is, throttle is a word with a broader meaning than constrain:

Other hypernyms of constrain include bound, confine, limit, restrict, trammel.

constrain (noun)	throttle (noun)
	a valve that regulates the supply of fuel to the engine
	a pedal that controls the throttle valve

constrain (verb)	throttle (verb)
severely restrict in scope or extent	reduce the air supply
to close within bounds, or otherwise limit or deprive of free movement	place limits on (extent or amount or access)
compel to behave in a certain way	kill by squeezing the throat of so as to cut off the air