a. [ L. mandatorius. ] 1. Containing a command; preceptive; directory. [ 1913 Webster ]
2. Obligatory; compulsory; required by authority. [ PJC ]
3. (Law) Not optional; not able to be modified or disregarded; as, seven mandatory clauses in the contract. [ PJC ]
n. Same as Mandatary. [ 1913 Webster ]