S: (n) spectator, witness, viewer, watcher, looker (a close observer; someone who looks at something (such as an exhibition of some kind)) "the spectators applauded the performance"; "television viewers"; "sky watchers discovered a new star"
S: (n) witness (testimony by word or deed to your religious faith)
S: (n) witness, attestant, attestor, attestator ((law) a person who attests to the genuineness of a document or signature by adding their own signature)
S: (n) cosigner, cosignatory (one of two or more signers of the same document (as a treaty or declaration))
S: (n) cosigner (a signer in addition to the principal signer (to verify the authenticity of the principal signature or to provide surety))
S: (n) abhorrer (a signer of a 1679 address to Charles II in which those who petitioned for the reconvening of parliament were condemned and abhorred)
S: (n) endorser, indorser (a person who transfers his ownership interest in something by signing a check or negotiable security)
S: (n) witness, attestant, attestor, attestator ((law) a person who attests to the genuineness of a document or signature by adding their own signature)
S: (n) witness ((law) a person who testifies under oath in a court of law)
Verb
S: (v) witness (be a witness to) "She witnessed the accident and had to testify in court"
S: (v) witness, find, see (perceive or be contemporaneous with) "We found Republicans winning the offices"; "You'll see a lot of cheating in this school"; "The 1960's saw the rebellion of the younger generation against established traditions"; "I want to see results"