Sentimental drunk found in the Seychelles (6)
I believe the answer is:
slushy
'sentimental' is the definition.
('slushy' can be a synonym of 'sentimental')
'drunk found in the seychelles' is the wordplay.
'drunk' becomes 'lush' (lush is a kind of drunk).
'found in' means one lot of letters goes inside another.
'the seychelles' becomes 'sy' (I've seen this in other clues).
'lush' inserted within 'sy' is 'SLUSHY'.
(Other definitions for slushy that I've seen before include "Mawkish" , "Like melting snow" , "Tritely sentimental" , "Schmaltzy" .)