The Collaborative International Dictionary of English v.0.48:
Angler \An"gler\, n.
1. One who angles.
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.