Realistic card for a trickster (9,5)
I believe the answer is:
practical joker
'trickster' is the definition.
(synonyms)
'realistic card' is the wordplay.
'realistic' becomes 'practical' (associated in meaning).
'card' becomes 'joker' (joker is a type of playing card).
'practical'+'joker'='PRACTICAL JOKER'
'for a' is the link.
(Other definitions for practical joker that I've seen before include "tricks, right up my street" , "Trickster" , "one who plays tricks" , "tricks are my speciality" .)