To attest to (a fact) as the truth.
To attest that a product, service, organization, or person has met an official standard.
To authenticate or verify in writing.
To deny, as a claim; to refuse.
To renounce all claim to; to deny ownership of or responsibility for; to disown; to disavow; to reject.
To make an admission or warning.
(law) To relinquish or deny having a claim; to disavow another's claim; to decline accepting, as an estate, interest, or office.