The sea god's possibly torn it (6)
I believe the answer is:
triton
'the sea god's' is the definition.
(figure of Greek myth)
'possibly torn it' is the wordplay.
'possibly' indicates anagramming the letters.
'torn'+'it'='tornit'
'tornit' is an anagram of 'TRITON'.
(Other definitions for triton that I've seen before include "Greek minor sea-god with trident, fish-tail and shell trumpet" , "conch-blowing deity" , "Satellite of Neptune - minor sea god" , "heavenly conch-blower" , "Trot in after sea-god, son of Poseidon" .)