We don't have synonyms for false note yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are false move, false name and false hope.
(n) :
(idiomatic, by extension) Of a remark or narrative, an indication (as discerned by the listener or reader) of untruth, insincerity, or inconsistency.
(n) :
(idiomatic, by extension) Of a non-verbal display or presentation, an indication of incongruity or inappropriateness.
(n) :
(music) An incorrect note which is sung or played in a musical performance.
(n) :
(idiomatic, by extension) Of a remark or narrative, an indication (as discerned by the listener or reader) of untruth, insincerity, or inconsistency.
(n) :
(idiomatic, by extension) Of a non-verbal display or presentation, an indication of incongruity or inappropriateness.
(n) :
(music) An incorrect note which is sung or played in a musical performance.