Almost spear a horned animal (6)
I believe the answer is:
impala
'horned animal' is the definition.
(type of antelope)
'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 final letter removed is 'impal'.
'impal'+'a'='IMPALA'
(Other definitions for impala that I've seen before include "Spectacular jumper" , "prodigious bounder" , "leaping creature" , "graceful African runner" , "Antelope with lyre-shaped horns" .)