Puzzles, games in play (7)
I believe the answer is:
enigmas
'puzzles' is the definition.
(an enigma is a puzzle or mystery)
'games in play' is the wordplay.
'play' indicates an anagram.
'games'+'in'='gamesin'
'gamesin' anagrammed gives 'ENIGMAS'.
(Other definitions for enigmas that I've seen before include "'Mysteries, riddles (7)'" , "They're mysterious or difficult to understand" , "Problems" , "'Puzzles, riddles (7)'" , "Puzzles - mysteries" .)