pre-emptor vs appropriator

pre-emptor and appropriator both are nouns.

Word	Noun	Adjective	Verb	Adverb
pre-emptor	Yes	No	No	No
appropriator	Yes	No	No	No

As nouns, appropriator is a hypernym of pre-emptor; that is, appropriator is a word with a broader meaning than pre-emptor:

pre-emptor: someone who acquires land by preemption
appropriator: someone who takes for his or her own use (especially without permission)

pre-emptor (noun)	appropriator (noun)
a bidder in bridge who makes a preemptive bid	someone who takes for his or her own use (especially without permission)
someone who acquires land by preemption