Wool or tall tale (4)
I believe the answer is:
yarn
I believe this is a double definition.
'wool' is the first definition.
(thesaurus)
'tall tale' is the second definition.
(I've seen this in another clue)
(Other definitions for yarn that I've seen before include "Rope" , "Anecdote" , "which could unravel?" , "Long involved story" , "Not fully credible story" .)