Signal returned by her playing card game (6)
I believe the answer is:
euchre
'card game' is the definition.
(euchre is a kind of card game)
'signal returned by her playing' is the wordplay.
'signal' becomes 'cue' (I've seen this before).
'returned' shows that the letters should be reversed in order.
'by' says to put letters next to each other.
'playing' is an anagram indicator.
'cue' reversed gives 'euc'.
'her' with letters rearranged gives 'hre'.
'euc'+'hre'='EUCHRE'
(Other definitions for euchre that I've seen before include "American card game" , "Card game with best, right and left bowers" , "American card-game" , "Game of cards" , "Outwit" .)