The Collaborative International Dictionary of English v.0.48:

Trim \Trim\, a. [Compar. Trimmer; superl. Trimmest.] [See
   Trim, v. t.]
   Fitly adjusted; being in good order., or made ready for
   service or use; firm; compact; snug; neat; fair; as, the ship
   is trim, or trim built; everything about the man is trim; a
   person is trim when his body is well shaped and firm; his
   dress is trim when it fits closely to his body, and appears
   tight and snug; a man or a soldier is trim when he stands
   erect.
   [1913 Webster]

         With comely carriage of her countenance trim.
                                                  --Spenser.
   [1913 Webster]

         So deemed I till I viewed their trim array
         Of boats last night.                     --Trench.
   [1913 Webster]