1. 
[syn: ceaseless, constant, incessant, never-ending, perpetual, unceasing, unremitting]
The Collaborative International Dictionary of English v.0.48:
never-ending \never-ending\ adj.
   endless or seemingly endless; as, the never-ending search for
   happiness.
   Syn: endless, interminable.
        [WordNet 1.5]
WordNet (r) 3.0 (2006):
never-ending
    adj 1: uninterrupted in time and indefinitely long continuing;
           "the ceaseless thunder of surf"; "in constant pain";
           "night and day we live with the incessant noise of the
           city"; "the never-ending search for happiness"; "the
           perpetual struggle to maintain standards in a democracy";
           "man's unceasing warfare with drought and isolation";
           "unremitting demands of hunger" [syn: ceaseless,
           constant, incessant, never-ending, perpetual,
           unceasing, unremitting]