control vs iron fist

control and iron fist both are nouns.

Word	Noun	Adjective	Verb	Adverb
control	Yes	No	Yes	No
iron fist	Yes	No	No	No

As nouns, iron fist is a hyponym of control; that is, iron fist is a word with a more specific, narrower meaning than control:

Other hyponyms of control include authorisation, authority, authorization, dominance, potency, say-so, corporatism, hold, rein.

control (noun)	iron fist (noun)
the activity of managing or exerting control over something	rigorous or ruthless control
(physiology) regulation or maintenance of a function or action or reflex etc
a mechanism that controls the operation of a machine
power to direct or determine
discipline in personal and social activities
great skillfulness and knowledge of some subject or activity
a standard against which other conditions can be compared in a scientific experiment
the economic policy of controlling or limiting or curbing prices or wages etc.
a spiritual agency that is assumed to assist the medium during a seance
a relation of constraint of one entity (thing or person or group) by another
the state that exists when one person or group has power over another

control (verb)	iron fist (verb)
have a firm understanding or knowledge of; be on top of
be careful or certain to do something; make certain of something
verify by using a duplicate register for comparison
handle and cause to function
maintain influence over (others or oneself) skillfully, usually to one's advantage
exercise authoritative control or power over
lessen the intensity of; temper; hold in restraint; hold or keep within limits
check or regulate (a scientific experiment) by conducting a parallel experiment or comparing with another standard
place under restrictions; limit access to by law