The Collaborative International Dictionary of English v.0.48:

Daft \Daft\ (d[.a]ft), a. [OE. daft, deft, deft, stupid; prob.
   the same word as E. deft. See Deft.]
   1. Stupid; foolish; idiotic; also, delirious; insane; as, he
      has gone daft.
      [1913 Webster]

            Let us think no more of this daft business --Sir W.
                                                  Scott.
      [1913 Webster]

   2. Gay; playful; frolicsome. [Scot.] --Jamieson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

daft
    adj 1: informal or slang terms for mentally irregular; "it used
           to drive my husband balmy" [syn: balmy, barmy,
           bats, batty, bonkers, buggy, cracked,
           crackers, daft, dotty, fruity, haywire,
           kooky, kookie, loco, loony, loopy, nuts,
           nutty, round the bend, around the bend, wacky,
           whacky]