Containing a caution, or warning to avoid danger: as, cautionary advice.Given as a pledge or in security.And it is resolved that it [a benevolence raised for the crown in Devon] shall only be employed for the payment of his debts, as namely for Ireland, the Navy, and the Cautionary Towns in the Low Countries; and so, leaving the carriage of this business to your discretions and wisdoms, we bid you heartily farewell.n. Same as cautionry.