Almost transfix a graceful antelope (6)
I believe the answer is:
impala
'graceful antelope' is the definition.
(I've seen this before)
'almost transfix a' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'transfix' becomes 'impale' ('impale' can be a synonym of 'transfix').
'impale' with its final letter removed is 'impal'.
'impal'+'a'='IMPALA'
(Other definitions for impala that I've seen before include "Species of African antelope" , "game animal" , "leaping creature" , "Antelope with lyre-shaped horns" , "Breed of antelope" .)