Wash and iron (7)
I believe the answer is:
'wash and iron' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for launder that I've seen before include "Wash and iron linen" , "Make illegal (money) legitimate" , "Led a run (anag)" , "Cleanse (material or money)" , "Perhaps decriminalise" .)