Some to choose from many a large antelope (5)
I believe the answer is:
nyala
'antelope' is the definition.
(nyala is a kind of antelope)
'some to choose from many a large' is the wordplay.
'some to choose from' indicates a hidden word (some letters from the clue must be chosen).
'NYALA' can be found hidden inside 'many a large'.
(Other definitions for nyala that I've seen before include "Large African antelope" , "Spiral-horned antelope" , "South African native" , "crested antelope" , "Antelope of southern Africa" .)