Slice of bacon (5)
'slice of bacon' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for rasher that I've seen before include "Thin slice of bacon" , "pig, to an extent" , "Slice of meat - more reckless" , "Tasty strip of bacon" , "taking more unnecessary risks?" .)
(Other definitions for strip that I've seen before include "footballers' outfit" , "Take off clothing" , "Thin piece" , "Dismantle" , "Team kit" .)