Crush, as potatoes (4)
I believe the answer is:
mash
'crush as potatoes' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for mash that I've seen before include "Crush, potatoes say" , "It goes well with sausages" , "Pulverise" , "Accompaniment of bangers" , "Pulped potatoes" .)