Fair Sex Meaning

(idiomatic, dated, now sometimes offensive) Women collectively.

Example: 1728, Daniel Defoe, Military Memoirs of Capt. George Carleton, ch. 8:
  The younger Gentry, or Dons, to express their Gallantry, carry about them Egg-shells, fill'd with Orange or other sweet Water, which they cast at Ladies in their Coaches, or such other of the fair Sex as they happen to meet in the Streets.
1820, Sir Walter Scott, The Abbot, ch. 23:
  "Permit me rather to perform my duty in attending them," said Roland, anxious to show he was possessed of the high tone of deference prescribed by the rules of chivalry towards the fair sex, and especially to dames and maidens of quality.
1922, D. H. Lawrence, "The Blind Man," in England, My England:
  And he had his friends among the fair sex—not lovers, friends.