Synonyms of testifiers

1 Syllable
proof
2 Syllables
signer, watcher, viewer, gawker
3 Syllables
observer, deponent, attester, onlooker, attestant, attestor, looker-on, beholder, bystander, eyewitness, spectator
4 Syllables
signatory, rubbernecker, testimony
5 Syllables
corroborator