The Collaborative International Dictionary of English v.0.48:

Becloud \Be*cloud"\, v. t. [imp. & p. p. Beclouded; p. pr. &
   vb. n. Beclouding.]
   To cause obscurity or dimness to; to dim; to cloud.
   [1913 Webster]

         If thou becloud the sunshine of thine eye. --Quarles.
   [1913 Webster]

WordNet (r) 3.0 (2006):

becloud
    v 1: make less visible or unclear; "The stars are obscured by
         the clouds"; "the big elm tree obscures our view of the
         valley" [syn: obscure, befog, becloud, obnubilate,
         haze over, fog, cloud, mist]

Moby Thesaurus II by Grady Ward, 1.0:

113 Moby Thesaurus words for "becloud":
   addle, addle the wits, ball up, bedarken, bedazzle, bedim, befog,
   befuddle, begloom, bemist, bewilder, black, black out, blacken,
   blanket, blind, block the light, blot out, blur, bother, brown,
   bug, camouflage, cast a shadow, clabber up, cloak, cloud,
   cloud over, cloud up, conceal, confuse, cover, cover up, curtain,
   darken, darken over, daze, dazzle, dim, dim out, discombobulate,
   discomfit, discompose, disconcert, disguise, disorganize,
   disorient, dissemble, distract attention from, disturb, eclipse,
   embarrass, encloud, encompass with shadow, enmist, ensconce,
   enshroud, entangle, envelop, flummox, flurry, fluster, flutter,
   fog, fuddle, fuss, gloom, gloss over, haze, hide, keep under cover,
   mask, maze, mist, mix up, moider, muddle, muddy, murk, nubilate,
   obfuscate, obnubilate, obscure, obumbrate, occult, occultate,
   opaque, overcast, overcloud, overshadow, oversmoke, perplex,
   perturb, pother, put out, puzzle, raise hell, rattle, ruffle,
   screen, shade, shadow, shroud, slur over, smog, smoke, somber,
   throw into confusion, unsettle, upset, varnish, veil, whitewash