Recurring theme (5)
(Other definitions for trope that I've seen before include "literary effect" , "figuratively speaking" , "Figure of speech - or pet (anag)" , "metaphor, perhaps" , "Figurative use of a word or expression; motif" .)
'recurring theme' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for motif that I've seen before include "Shape" , "artistic figure" , "sign" , "recurring idea" , "Concept" .)