verb intrans
to give evidence under oath as a witness in a court
(usu + to) to serve as evidence or proof
to make a statement based on personal knowledge or belief
to affirm the truth of (something)
to serve as evidence of (something)
to make known (a personal conviction)
to declare (something) under oath
testifier noun
[Middle English testifien from Latin testificari, from testis witness, testis]