Some loony alarmed antelope (5)
I believe the answer is:
nyala
'antelope' is the definition.
(nyala is a kind of antelope)
'some loony alarmed' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'NYALA' can be found hidden inside 'loony alarmed'.
(Other definitions for nyala that I've seen before include "beast" , "Antelope of southern Africa" , "Large African antelope" , "one of a herd" , "Ruminant" .)