Source : Webster's Revised Unabridged Dictionary (1913)

Inattentive \In`at*ten"tive\, a. [Cf. F. inattentif.]
   Not attentive; not fixing the mind on an object; heedless;
   careless; negligent; regardless; as, an inattentive spectator
   or hearer; an inattentive habit. --I. Watts.

   Syn: Careless; heedless; regardless; thoughtless; negligent;
        remiss; inadvertent. -- {In`at*ten"tive*ly}, adv. --
        {In`at*ten"tive*ness}, n.

Source : WordNet®

inattentiveness
     n 1: a lack of attentiveness (as to children or helpless people)
          [syn: {heedlessness}] [ant: {attentiveness}]
     2: the trait of not being considerate and thoughtful of others
        [ant: {attentiveness}]