trainer vs handler

trainer and handler both are nouns.

Word	Noun	Adjective	Verb	Adverb
trainer	Yes	No	No	No
handler	Yes	No	No	No

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

Other hyponyms of trainer include coach, manager, animal trainer.

trainer (noun)	handler (noun)
simulator consisting of a machine on the ground that simulates the conditions of flying a plane	(sports) someone in charge of training an athlete or a team
one who trains other persons or animals	one who trains or exhibits animals
	an agent who handles something or someone