hatter 1
/hat"euhr/ , n.
a maker or seller of hats.
[ 1350-1400; ME; see HAT, -ER 1 ]
hatter 2
/hat"euhr/ , n. Australian Informal.
1. a person who has become eccentric from living alone in a remote area.
2. a person who lives alone in the bush, as a herder or prospector.
[ 1850-55; said to be from the phrase "as mad as a hatter" ]