Guy in Love Island is a horny bounder (5)
I believe the answer is:
oribi
'a horny bounder' is the definition.
(type of antelope - something which bounds around)
'guy in love island' is the wordplay.
'guy' becomes 'rib' (both can mean to tease).
'in' indicates putting letters inside.
'love' becomes 'o' (love means zero in tennis).
'island' becomes 'i' (geographical abbreviation).
'o'+'i'='oi'
'rib' inserted into 'oi' is 'ORIBI'.
'is' is the link.
(Other definitions for oribi that I've seen before include "Small African antelope" , "Beastly sort" , "small hoofed beast" , "Savannah antelope" , "Graceful runner" .)