The Collaborative International Dictionary of English v.0.48:

Beetle \Bee"tle\ (b[=e]"t'l), v. t. [imp. & p. p. Beetled
   (-t'ld); p. pr. & vb. n. Beetling.]
   1. To beat with a heavy mallet.
      [1913 Webster]

   2. To finish by subjecting to a hammering process in a beetle
      or beetling machine; as, to beetle cotton goods.
      [1913 Webster]

WordNet (r) 3.0 (2006):

beetling
    adj 1: jutting or overhanging; "beetle brows" [syn: beetle,
           beetling]