The Collaborative International Dictionary of English v.0.48:

Recumb \Re*cumb"\ (-k?m"), v. i. [L. recumbere; pref. re- back +
   cumbere (in comp.), akin to cubare to lie down.]
   To lean; to recline; to repose. [Obs.] --J. Allen (1761).
   [1913 Webster]

WordNet (r) 3.0 (2006):

recumb
    v 1: lean in a comfortable resting position; "He was reposing on
         the couch" [syn: recumb, repose, recline]