lackey vs bootlicker

lackey and bootlicker both are nouns.

Word	Noun	Adjective	Verb	Adverb
lackey	Yes	No	No	No
bootlicker	Yes	No	No	No

As nouns, bootlicker is a hyponym of lackey; that is, bootlicker is a word with a more specific, narrower meaning than lackey:

lackey: a person who tries to please someone in order to gain a personal advantage
bootlicker: someone who humbles himself as a sign of respect; who behaves as if he had no self-respect

Other hyponyms of lackey include apple polisher, fawner, groveler, groveller, truckler, goody-goody.

lackey (noun)	bootlicker (noun)
a male servant (especially a footman)	someone who humbles himself as a sign of respect; who behaves as if he had no self-respect
a person who tries to please someone in order to gain a personal advantage