larcenist vs stealer

larcenist and stealer both are nouns.

Word	Noun	Adjective	Verb	Adverb
larcenist	Yes	No	No	No
stealer	Yes	No	No	No

As nouns, stealer is a hypernym of larcenist; that is, stealer is a word with a broader meaning than larcenist:

larcenist: a person who commits larceny
stealer: a criminal who takes property belonging to someone else with the intention of keeping it or selling it

Other hypernyms of larcenist include thief.

larcenist (noun)	stealer (noun)
a person who commits larceny	a criminal who takes property belonging to someone else with the intention of keeping it or selling it