The Collaborative International Dictionary of English v.0.48:

Recumbent \Re*cum"bent\ (-bet), a. [L. recumbens, -entis, p. pr.
   of recumbere. See Recumb, Incumbent.]
   Leaning; reclining; lying; as, the recumbent posture of the
   Romans at their meals. Hence, figuratively; Resting;
   inactive; idle. -- Re*cum"bent*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

recumbent
    adj 1: lying down; in a position of comfort or rest [syn:
           accumbent, decumbent, recumbent]