impression vs suspicion

impression and suspicion both are nouns.

Word	Noun	Adjective	Verb	Adverb
impression	Yes	No	No	No
suspicion	Yes	No	No	No

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

Other hyponyms of impression include presence, effect, first blush, hunch, intuition.

impression (noun)	suspicion (noun)
an impressionistic portrayal of a person	being of a suspicious nature
the act of pressing one thing on or into the surface of another	doubt about someone's honesty
(dentistry) an imprint of the teeth and gums in wax or plaster	an impression that something might be the case
an outward appearance	the state of being suspected
a vague idea in which some confidence is placed
a clear and telling mental image
a symbol that is the result of printing or engraving
all the copies of a work printed at one time
a concavity in a surface produced by pressing