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."
1590s, "entrusted, delegated," past-participle adjective from commit (v.). Meaning "characterized by commitment" is from 1948.
From 1620s as "body of persons, appointed or elected, to whom some special business or function has been entrusted;" a new formation or else an extended sense of the old noun. Related: Committeeman; committeeship.
late 14c., "one to whom special duty is entrusted by a higher power," from Medieval Latin commissarius, from Latin commissus "entrusted," past participle of committere (see commit).
Originally especially ecclesiastical, "one who performs a bishop's duties in distant places or when he is absent;" the military sense of "official in charge of supply of food, stores, and transport" dates to late 15c. Hence "storeroom" (1882, U.S. military), especially for selling articles to persons engaged in a particular line of work, and then "dining room in a larger facility" (1924, American English), such as a movie studio.
mid-14c., comenden, "praise, mention approvingly," from Latin commendare "to commit to the care or keeping (of someone), to entrust to; to commit to writing;" hence "to set off, render agreeable, praise," from com-, here perhaps an intensive prefix (see com-), + mandare "to commit to one's charge" (see mandate (n.)). A doublet of command.
Sense of "commit, deliver with confidence" in English is from late 14c. Meaning "bring to mind, send the greeting of" is from c. 1400. The "praise" sense is from the notion of "present as worthy of notice or regard;" also in some cases probably a shortening of recommend. Related: Commended; commending.