Source : Webster's Revised Unabridged Dictionary (1913)

Fitful \Fit"ful\, a. [From 7th {Fit}.]
   Full of fits; irregularly variable; impulsive and unstable.

         After life's fitful fever, he sleeps well. --Shak.
   -- {Fit"ful*ly}, adv. -- {Fit"ful*ness}, n.

         The victorious trumpet peal Dies fitfully away.
                                                  --Macaulay.

Source : WordNet®

fitful
     adj 1: occurring in spells and often abruptly; "fitful bursts of
            energy"; "spasmodic rifle fire" [syn: {spasmodic}]
     2: intermittently stopping and starting; "fitful (or
        interrupted) sleep"; "off-and-on static" [syn: {interrupted},
         {off-and-on(a)}]