Flimsy paper kept in folder (7)
I believe the answer is:
fragile
'flimsy' is the definition.
(I've seen this before)
'paper kept in folder' is the wordplay.
'paper' becomes 'rag' (rag can mean a newspaper).
'kept in' indicates putting letters inside.
'folder' becomes 'file folder' (file folder is a kind of folder).
'rag' going within 'file' is 'FRAGILE'.
(Other definitions for fragile that I've seen before include "Weak" , "Rag file is easily broken" , "Liable to break easily" , "Not robust" , "To be handled with care" .)