combat boot vs top boot

combat boot and top boot both are nouns.

Word	Noun	Adjective	Verb	Adverb
combat boot	Yes	No	No	No
top boot	Yes	No	No	No

As nouns, combat boot and top boot are synonyms defined as:

Other synonyms of combat boot include buskin, desert boot, half boot.

combat boot (noun)	top boot (noun)
a boot reaching halfway up to the knee	a boot reaching halfway up to the knee
A type of heavy leather lace-up boot adopted mainly by heavy metal, punk and goth subcultures; comes in different colors and heights which are measured in the number of eyelets.