Almost spear a beast (6)
I believe the answer is:
impala
'beast' is the definition.
(I've seen this before)
'almost spear a' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'spear' becomes 'impale'.
'impale' with its last letter taken off is 'impal'.
'impal'+'a'='IMPALA'
(Other definitions for impala that I've seen before include "Graceful antelope" , "Big game" , "Antelope with lyre-shaped horns" , "Spectacular jumper" , "horny creature" .)