The Collaborative International Dictionary of English v.0.48:

Hatter \Hat"ter\ (-t[~e]r), v. t. [Prov. E., to entangle; cf.
   LG. verhaddern, verheddern, verhiddern.]
   To tire or worry; -- with out. [Obs.] --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Hatter \Hat"ter\, n.
   One who makes or sells hats.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hatter
    n 1: someone who makes and sells hats [syn: hatmaker,
         hatter, milliner, modiste]