witnesser

Synonyms:

informant, witness

Types:

attestant, attester

someone who affirms or vouches for the correctness or truth or genuineness of something

deponent, deposer, testifier

a person who testifies or gives a deposition

Type of:

beholder, observer, perceiver, percipient

a person who becomes aware (of things or events) through the senses

speaker, talker, utterer, verbaliser, verbalizer

someone who expresses in language; someone who talks (especially someone who delivers a public speech or someone especially garrulous)