desert boot vs top boot

desert boot and top boot both are nouns.

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

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

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

desert boot (noun)	top boot (noun)
a boot reaching halfway up to the knee	a boot reaching halfway up to the knee