Oriental seabird overwhelmed by raging sea (7)
I believe the answer is:
eastern
'oriental' is the definition.
(similar in meaning)
'seabird overwhelmed by raging sea' is the wordplay.
'seabird' becomes 'tern' (tern is a kind of seabird).
'overwhelmed by' means one lot of letters go next to another (in a down clue, some letters go on top of others).
'raging' indicates an anagram.
'sea' anagrammed gives 'eas'.
'tern' after 'eas' is 'EASTERN'.
(Other definitions for eastern that I've seen before include "Coming from the Orient" , "from afar" , "Chinese', for example" , "Of the direction of the rising sun" , "See 11" .)