1. (v. t.) To bear witness to; to certify; to affirm to be genuine; as, to attest the truth of a writing\.

2. (v. t.) To give proof of; to manifest; as, the ruins of Palmyra attest its ancient magnificence.

3. (v. t.) To call to witness; to invoke.

4. (n.) Witness; testimony; attestation.

acknowledge affirm allege and candle announce approve argue assert assert under oath asseverate assure authenticate aver avouch avow back back up be sponsor for bear out bear witness bespeak betoken bolster bond book breathe buttress certify circumstantiate confirm connote corroborate countersecure declare demonstrate denote depone depose disclose display document endorse ensure evidence evince exhibit express fortify furnish evidence give evidence give indication of go to show guarantee guaranty illustrate imply indicate insure involve kiss the book manifest mark point to probate prove ratify reinforce secure set forth show show signs of sign sign for signalize signify speak for itself speak volumes sponsor stand behind stand up for strengthen subscribe to substantiate suggest support sustain swear swear by bell swear the truth swear to swear to God swear to goodness symptomatize tell tend to show testify undergird undersign underwrite uphold validate verify vouch vouch for vouchsafe vow warrant witness