Origin: before 900; probably continuing Old Englishtrymman, trymian to strengthen, prepare (not recorded in ME), derivative of trum strong, active; akin to Irishdron strong, Greekdrȳmós coppice, Latindūrus hard. See tree
probably from O.E. trymman "strengthen, make ready," from trum "strong, stable," from P.Gmc. *trumaz; said to be cognate with Skt. drumah "tree," Gk. drymos "copse, thicket," drys "tree, oak," and O.E. treow (see tree). Examples in M.E. are wanting. Original sense is preserved
in nautical phrase in fighting trim (see trim (n.)). Meaning "make neat by cutting" is first recorded 1530; that of "decorate, adorn" is from 1547. Sense of "reduce" is attested from 1966. The adj. sense of "in good condition, neat, fit" is attested from 1503, probably ult. from O.E. adj. trum.
trim
"state of being prepared," 1590, nautical jargon, from trim (v.). The meaning "visible woodwork of a house" is recorded from 1884; sense of "ornamental additions to an automobile" is from 1922. Slang meaning "a woman regarded as a sex object" is attested from 1955, Amer.Eng.