[1] : The Collaborative International Dictionary of English v.0.48

overcloud \o`vercloud"\, v. t.
   to cover or overspread with clouds; to becloud; to overcast.
   1913 webster

[2] : WordNet (r) 2.0

overcloud
     v 1: become covered with clouds; "the sky clouded over" syn: cloud
          over, cloud up
     2: make obscure or unclear; "the distinction was obscured"
        syn: obscure, bedim
see also:
cloud over cloud up obscure bedim 

Overcloud >> O Words
Overcloud, definition of term: Overcloud
overcloud_pag1.html