warrant

(noun) a writ from a court commanding police to perform specified acts.

(noun) a 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. Synonyms: stock warrant, stock-purchase warrant. Example: "As a sweetener they offered warrants along with the fixed-income securities."

(noun) formal and explicit approval. Synonyms: sanction, countenance, endorsement, indorsement, imprimatur. Example: "A democrat usually gets the union's endorsement."

(noun) a written assurance that some product or service will be provided or will meet certain specifications. Synonyms: guarantee, warrantee, warranty.

(verb) show to be reasonable or provide adequate ground for. Synonyms: justify. Examples: "The emergency does not warrant all of us buying guns." "The end justifies the means."

(verb) stand behind and guarantee the quality, accuracy, or condition of. Synonyms: guarantee. Examples: "The dealer warrants all the cars he sells." "I warrant this information."