authorization, sanction, or justification.

something that serves to give reliable or formal assurance of something; guarantee, pledge, or security.

something considered as having the force of a guarantee or as being positive assurance of a thing

The cavalry and artillery were considered sure warrants of success.

a writing or document certifying or authorizing something, as a receipt, license, or commission.

Law . an instrument, issued by a magistrate, authorizing an officer to make an arrest, seize property, make a search, or carry a judgment into execution.

the certificate of authority or appointment issued to an officer of the armed forces below the rank of a commissioned officer.

a warehouse receipt.

a written authorization for the payment or receipt of money

a treasury warrant.

to give authority to; authorize.

to give reason or sanction for; justify

The circumstances warrant such measures.

to give one's word for; vouch for (often used with a clause to emphasize something asserted)

I'll warrant he did!

to give a formal assurance, or a guarantee or promise, to or for; guarantee

to warrant someone honorable treatment; to warrant payment; to warrant safe delivery.

to guarantee the quantity, quality, and other representations of (an article, product, etc.), as to a purchaser.

to guarantee or secure title to (the purchaser of goods); assure indemnification against loss to.

Law . to guarantee title of an estate or other granted property (to a grantee).

noun

breach , break

noun

accreditation , assurance , authentication , authority , basis , carte blanche , certificate , commission , credential , credentials , ducat , earnest , foundation , go-ahead * , green light * , guarantee , license , official document , okay * , pass , passport , pawn , permission , permit , pledge , right , sanction , security , shingle , sticker , subpoena , summons , tag , testimonial , ticket , token , verification , warranty , word , justification , reason , attestation , corroboration , demonstration , evidence , proof , substantiation , testament , testimony , validation , guaranty , surety , covenant , engagement , plight , solemn word , vow , word of honor

verb

affirm , answer for , approve , argue , assert , assure , attest , avouch , back , bear out , call for , certify , claim , commission , contend , declare , defend , delegate , demand , empower , endorse , ensure , entitle , excuse , explain , give grounds for , guaranty , insure , license , maintain , necessitate , permit , pledge , privilege , promise , require , sanction , secure , sponsor , stand behind , state , stipulate , swear , take an oath , undertake , underwrite , uphold , vindicate , vouch for , vow , authenticate , corroborate , evidence , justify , substantiate , testify , validate , verify , occasion , assurance , authority , authorization , authorize , certificate , document , foundation , grounds , guarantee , guard , justification , obligation , order , permission , proof , protect , protection , reason , right , safeguard , subpoena , vouch , voucher , writ