In Ireland, an antelope (5)
I believe the answer is:
eland
'antelope' is the definition.
(eland is a kind of antelope)
'in ireland an' is the wordplay.
'in' says the answer is hidden in the clue.
'ELAND' is hidden within 'ireland an'.
(Other definitions for eland that I've seen before include "Large spiral-horned African antelope" , "Browser" , "Ruminant" , "Animal's" , "One browses in the African plain" .)