ratter noun. 
['ratǝ] ME.[from RAT noun1, verb1 + -ER1.]1.  A rat-catcher; 
esp. a dog or cat which catches rats. 
ME.2.  = 
RAT noun1 2b, c. 
slang. 
M19.3.  A person who steals opal from another's mine. 
Austral. slang. 
M20.  [TahlilGaran] English Dictionary ▲