1530s, "to windward," from a- (1) "on" + Middle English loof "windward direction," probably from Dutch loef (Middle Dutch lof) "the weather side of a ship" (see luff (n.)). Originally in nautical orders to keep the ship's head to the wind, thus to stay clear of a lee-shore or some other quarter; hence "at a distance but within view" (1530s) and, figuratively, "apart, withdrawn, without community spirit" (with verbs stand, keep, etc.). As an adjective from c. 1600. Related: Aloofly; aloofness.