The Collaborative International Dictionary of English v.0.48:

Addle-brain \Ad"dle-brain`\, Addle-head \Ad"dle-head`\,
Addle-pate \Ad"dle-pate\, n.
   A foolish or dull-witted fellow. [Colloq.]
   [1913 Webster] Addle-headed
   Addle-brained