Almost committing murder (2,2)
I believe the answer is:
do in
'murder' is the definition.
(I've seen this before)
'almost committing' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'committing' becomes 'doing'.
'doing' with its last letter taken away is 'DO IN'.
(Other definitions for do in that I've seen before include "Knock off" , "Get rid of" , "Murder" .)