der·o·gate / ˈderəˌgāt/ • v. formal 1. [tr.] disparage (someone or something): it is typical of Pirandello to derogate the powers of reason.2. [intr.] (derogate from) detract from: this does not derogate from his duty to act honestly and faithfully.3. [intr.] (derogate from) deviate from (a set of rules or agreed form of behavior): one country has derogated from the Rome Convention.DERIVATIVES: de·rog·a·tive / diˈrägətiv/ adj.

derogate †abrogate in part; †detract from, disparage; take away a part from XV; fall away from a standard XVII. f. pp. stem of L. dērogāre, f. DE- 2 + rogāre ask, question, propose (a law).
So derogation XV. — (O)F. or L. derogatory XVI. — late L.