Definition of "Untrue" :

adjective: (used especially of persons) not dependable in devotion or affection; unfaithful

"When lovers prove untrue."

adjective: not accurately fitted; not level

"Off-level floors and untrue doors and windows."

adjective: not true to an obligation or trust

"Is untrue to his highest opportunity and duty."

adjective: not according with the facts

"Unfortunately the statement was simply untrue."