Gift adult left in shelter (6)
I believe the answer is:
talent
'gift' is the definition.
('talent' can be a synonym of 'gift')
'adult left in shelter' is the wordplay.
'adult' becomes 'a'.
'left' becomes 'l' (common abbreviation).
'in' is an insertion indicator.
'shelter' becomes 'tent' (tent is a kind of shelter**).
'a'+'l'='al'
'al' put within 'tent' is 'TALENT'.
(Other definitions for talent that I've seen before include "Flair, aptitude" , "Natural ability or aptitude" , "Innate ability, flair" , "Natural skill or flair" , "Natural ability or flair" .)