Fish cleaner (4)
I believe the answer is:
char
I believe this is a double definition.
'fish' is the first definition.
(char is a kind of fish)
'cleaner' is the second definition.
(charwoman is a type of cleaner)
(Other definitions for char that I've seen before include "Cleaner - tea" , "Tea - cleaning lady" , "Daily cleaner; burn" , "One cleans" , "way to make carbon" .)