Is coming over about affected seafood (6)
I believe the answer is:
scampi
'seafood' is the definition.
(I've seen this before)
'is coming over about affected' is the wordplay.
'coming over' says the letters should be written in reverse.
'about' means one lot of letters goes inside another.
'affected' becomes 'camp' (I've seen this before).
'is' back-to-front is 'si'.
'si' going around 'camp' is 'SCAMPI'.
(Other definitions for scampi that I've seen before include "sort of seafood" , "Crumby seafood dish" , "Large prawns cooked in batter" , "Breaded prawns" , "Prawns, usually fried" .)