The Collaborative International Dictionary of English v.0.48:

Listless \List"less\, a. [OE. listles, lustles. See Lust.]
   Having no desire or inclination; indifferent; heedless;
   spiritless. " A listless unconcern." --Thomson.
   [1913 Webster]

         Benumbed with cold, and listless of their gain.
                                                  --Dryden.
   [1913 Webster]

         I was listless, and desponding.          --Swift.

   Syn: Heedless; careless; indifferent; vacant; uninterested;
        languid; spiritless; supine; indolent. --
        List"less*ly, adv. -- List"less*ness, n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

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, listless]

The Free On-line Dictionary of Computing (19 January 2023):

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)