seer vs perceiver

seer and perceiver both are nouns.

Word	Noun	Adjective	Verb	Adverb
seer	Yes	No	No	No
perceiver	Yes	No	No	No

As nouns, perceiver is a hypernym of seer; that is, perceiver is a word with a broader meaning than seer:

seer: an observer who perceives visually
perceiver: a person who becomes aware (of things or events) through the senses

Other hypernyms of seer include beholder, observer, percipient.

seer (noun)	perceiver (noun)
a person with unusual powers of foresight	a person who becomes aware (of things or events) through the senses
an authoritative person who divines the future
an observer who perceives visually