Disloyal (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
false
'disloyal' is the definition.
(associated in meaning)
This is all the clue.
(Other definitions for false that I've seen before include "Spurious, untrue" , "Invalid; untrue" , "Erroneous" , "Misleading" , "Untrue - treacherous - counterfeit" .)