Waterlogged planet hastily evacuated (6)
I believe the answer is:
marshy
'waterlogged' is the definition.
(I know that waterlogged can be written as marshy)
'planet hastily evacuated' is the wordplay.
'planet' becomes 'mars' (Mars is a planet).
'evacuated' means to remove the middle letters (internal letters are evacuated from the word).
'hastily' with its middle taken out is 'hy'.
'mars'+'hy'='MARSHY'
(Other definitions for marshy that I've seen before include "Damp and low-lying" , "Like swamps" , "Wet and low-lying" , "Boggy; waterlogged" , "like Slough" .)