untrue

adjective
1
not true; not based on facts
نادرست, کاذب, غیرواقعی, بی‌پایه, بدون اساس
2
not loyal to somebody/something; doing something that hurts or damages somebody/something
بی‌وفا, خائن, خیانت‌آمیز
If he agreed to their demands, he would have to be untrue to his own principles.
opposite true