Nouns

(n)warranta writ from a court commanding police to perform specified acts
(n)warrant, stock warrant, stock-purchase warranta type of security issued by a corporation (usually together with a bond or preferred stock) that gives the holder the right to purchase a certain amount of common stock at a stated price“as a sweetener they offered warrants along with the fixed-income securities”
(n)sanction, countenance, endorsement, indorsement, warrant, imprimaturformal and explicit approval“a Democrat usually gets the union's endorsement”
(n)guarantee, warrant, warrantee, warrantya written assurance that some product or service will be provided or will meet certain specifications

Verbs

(v)warrantprovide adequate grounds to justify (a certain course of action)“The emergency does not warrant all of us buying guns”
(v)guarantee, warrantstand behind and guarantee the quality, accuracy, or condition of“The dealer warrants all the cars he sells”, “I warrant this information”