The Collaborative International Dictionary of English v.0.48:

Angler \An"gler\, n.
   1. One who angles.
      [1913 Webster]

   2. (Zool.) A fish (Lophius piscatorius), of Europe and
      America, having a large, broad, and depressed head, with
      the mouth very large. Peculiar appendages on the head are
      said to be used to entice fishes within reach. Called also
      fishing frog, frogfish, toadfish, goosefish,
      allmouth, monkfish, etc.
      [1913 Webster]

WordNet (r) 3.0 (2006):

angler
    n 1: a scheming person; someone who schemes to gain an advantage
    2: a fisherman who uses a hook and line [syn: angler,
       troller]
    3: fishes having large mouths with a wormlike filament attached
       for luring prey [syn: goosefish, angler, anglerfish,
       angler fish, monkfish, lotte, allmouth, Lophius
       Americanus]