Rotten gamer goes up to conceal attractive item (6)
I believe the answer is:
magnet
'attractive item' is the definition.
(I've seen this in another clue)
'rotten gamer goes up to conceal' is the wordplay.
'to conceal' indicates the answer is hidden within the clue.
'goes up' is a reversal indicator.
'tengam' can be found hidden inside 'rotten gamer'.
'tengam' written backwards gives 'MAGNET'.
(Other definitions for magnet that I've seen before include "Attractive piece of metal" , "One that attracts" , "Piece of metal that attracts iron" , "Focus of attraction" , "Attractor of iron" .)