Poetic pond (4)
I believe the answer is:
mere
'poetic pond' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for mere that I've seen before include "Lake (poetic); Maori war club" , "Simply, nothing more than" , "See 13" , "Nothing more than - water" , "Unimpressive" .)