Pieces of stiff paper (5)
I believe the answer is:
cards
'pieces of stiff paper' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for cards that I've seen before include "jokers" , "Small pieces of stiff paper" , "With which to play snap or patience, perhaps" , "Odd people" , "Combs (wool); pack of --" .)