clamp down vs throttle

clamp down is not a noun while throttle is a noun.

Word	Noun	Adjective	Verb	Adverb
clamp down	No	No	Yes	No
throttle	Yes	No	Yes	No

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

Other hypernyms of clamp down include bound, confine, limit, restrict, trammel.

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

clamp down (verb)	throttle (verb)
repress or suppress (something regarded as undesirable)	reduce the air supply
	place limits on (extent or amount or access)
	kill by squeezing the throat of so as to cut off the air