Source : Webster's Revised Unabridged Dictionary (1913)

Listless \List"less\, a. [OE. listles, lustles. See {Lust}.]
   Having no desire or inclination; indifferent; heedless;
   spiritless. `` A listless unconcern.'' --Thomson.

         Benumbed with cold, and listless of their gain.
                                                  --Dryden.

         I was listless, and desponding.          --Swift.

   Syn: Heedless; careless; indifferent; vacant; uninterested;
        languid; spiritless; supine; indolent. --
        {List"less*ly}, adv. -- {List"less*ness}, n.

Source : WordNet®

listless
     adj 1: lacking zest or vivacity; "he was listless and bored"
     2: marked by low spirits; showing no enthusiasm; "a dispirited
        and divided Party"; "reacted to the crisis with listless
        resignation" [syn: {dispirited}]

Source : Free On-Line Dictionary of Computing

listless
     
         In {functional programming}, a property of a
        {function} which allows it to be combined with other functions
        in a way that eliminates intermediate data structures,
        especially lists.
     
        {Phil Wadler}'s thesis gives the conditions for a function to
        be in listless form: each input list is traversed only once,
        one element at a time, from left to right.  Each output list
        is generated once, one element at a time, from left to right.
        No other lists are generated or traversed.
     
        Not all functions can be expressed in listless form
        (e.g. reverse).
     
        (1995-02-22)