Attitude I assume is Olympian (8)
I believe the answer is:
poseidon
'olympian' is the definition.
(Greek god who lived on Mount Olympus)
'attitude i assume' is the wordplay.
'attitude' becomes 'pose' (attitude can mean a pose or stance).
'assume' becomes 'don' (I've seen this in another clue).
'pose'+'i'+'don'='POSEIDON'
'is' is the link.
(Other definitions for poseidon that I've seen before include "Sea Lord" , "underwater missile" , "I snooped to find Greek god of the sea" , "being able to create waves?" , "associated with adventure on screen" .)