Runs from disagreement? That’s a lie (7)
I believe the answer is:
fiction
'that's a lie' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
(Other definitions for fiction that I've seen before include "Non-factual story" , "Imaginary prose" , "Fabricated story" , "Invented story" , "Something invented" .)