Kitten's plaything (4)
I believe the answer is:
yarn
'kitten's plaything' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for yarn that I've seen before include "Long involved story" , "Not fully credible story" , "Rambling tale" , "Cord of twisted fibres, wool say" , "Sham" .)