lackey vs ass-kisser

lackey and ass-kisser both are nouns.

Word	Noun	Adjective	Verb	Adverb
lackey	Yes	No	No	No
ass-kisser	Yes	No	No	No

As nouns, lackey and ass-kisser are synonyms defined as:

lackey and ass-kisser: a person who tries to please someone in order to gain a personal advantage

Other synonyms of lackey include crawler, sycophant, toady.

lackey (noun)	ass-kisser (noun)
a male servant (especially a footman)	a person who tries to please someone in order to gain a personal advantage
a person who tries to please someone in order to gain a personal advantage