iron heel vs iron boot

iron heel and iron boot both are nouns.

Word	Noun	Adjective	Verb	Adverb
iron heel	Yes	No	No	No
iron boot	Yes	No	No	No

As nouns, iron heel and iron boot are synonyms defined as:

iron heel and iron boot: an instrument of torture that is used to heat or crush the foot and leg

Other synonyms of iron heel include boot, the boot.

iron heel (noun)	iron boot (noun)
an instrument of torture that is used to heat or crush the foot and leg	an instrument of torture that is used to heat or crush the foot and leg