The Collaborative International Dictionary of English v.0.48:

Daftness \Daft"ness\, n.
   The quality of being daft.
   [1913 Webster]

WordNet (r) 3.0 (2006):

daftness
    n 1: informal terms for insanity [syn: craziness, daftness,
         flakiness]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "daftness":
   aberration, abnormality, alienation, brain damage, brainsickness,
   clouded mind, craziness, dementedness, dementia, derangement,
   disorientation, distraction, folie, furor, insaneness, insanity,
   irrationality, loss of mind, loss of reason, lunacy, madness,
   mania, mental deficiency, mental derangement, mental disease,
   mental disorder, mental disturbance, mental illness,
   mental instability, mental sickness, mind overthrown, mindsickness,
   oddness, pixilation, possession, queerness, rabidness,
   reasonlessness, senselessness, shattered mind, sick mind, sickness,
   strangeness, unbalance, unbalanced mind, unsaneness, unsound mind,
   unsoundness, unsoundness of mind, witlessness