Aunt Enid floundering in swamp (8)
I believe the answer is:
inundate
'swamp' is the definition.
(I know that swamp can be written as inundate)
'aunt enid floundering' is the wordplay.
'floundering' indicates anagramming the letters (letters flounder or move around).
'aunt'+'enid'='auntenid'
'auntenid' anagrammed gives 'INUNDATE'.
'in' acts as a link.
(Other definitions for inundate that I've seen before include "Flood (a place)" , "Submerge or cover in water" , "'Flood, swamp (8)'" , "Flood, cover with water" , "Flood, fill completely" .)