Gory corpse has little oedema initially (6)
I believe the answer is:
bloody
'gory' is the definition.
(similar in meaning)
'corpse has little oedema initially' is the wordplay.
'corpse' becomes 'body' (I've seen this before).
'has' is an insertion indicator.
'initially' says to take the initial letters.
The first letters of 'little oedema' is 'lo'.
'body' going around 'lo' is 'BLOODY'.
(Other definitions for bloody that I've seen before include ""____ but unbowed"" , "Cruel, murderous" , "Gory" .)