Swamp is still ok to use after UN leaves (8)
I believe the answer is:
inundate
'swamp' is the definition.
(I know that swamp can be written as inundate)
'still ok to use after un leaves' is the wordplay.
I cannot quite understand how this works, but
'un' is within the answer.
This explanation may well be incorrect...
'is' acts as a link.
Can you help me to learn more?
(Other definitions for inundate that I've seen before include "Submerge or cover in water" , "Flood, fill completely" , "Aunt Enid could engulf badly" , "Overwhelm (as if) with water" , "Overrun" .)