commissary n.

late 14c., "to give in charge, entrust," from Latin committere "to unite, connect, combine; to bring together," from com "with, together" (see com-) + mittere "to release, let go; send, throw" (see mission).

The evolution of the modern range of meanings in English is not entirely clear. Sense of "to perpetrate (a crime), do, perform (especially something reprehensible)" was ancient in Latin; in English it is attested from mid-15c. Meaning "consign (someone) to custody (of prison, a mental institution, etc.) by official warrant" is from early 15c.

From 1530s as "trust (oneself) completely to;" from 1770 as "put or bring into danger by an irrevocable preliminary act." The intransitive use (in place of commit oneself) first recorded 1982, probably influenced by existentialism use (1948) of commitment to translate Sartre's engagement "emotional and moral engagement."

in a Russian context, "representative appointed by a soviet and responsible for political indoctrination," 1918, from Russian komissar, from German Kommissar "commissioner," from French commissaire, ultimately from Medieval Latin commissarius (see commissary). Earlier in English it meant "commissary" (1640s), from the French word, which itself was used in English from 1753.

c. 1600, in Scottish law, "commissary court," from French commissariat, from Medieval Latin *commissariatus, from commissarius (see commissary). Military sense of "part of an army that supplies transport, provisions, camp equipment, etc.," is from 1779. In reference to the USSR, "ministry," from 1918 (see commissar).