top boot vs combat boot

top boot and combat boot both are nouns.

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

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

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

top boot (noun)	combat 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.