na-adjective, noun which may take the genitive case particle 'no', noun
unfaithful; insincere; perfidious
Describes a person, action, or attitude lacking sincerity, loyalty, or truthfulness. Often used in formal or literary contexts to criticize betrayal or dishonesty.
彼の不実な態度に失望した。
I was disappointed by his insincere attitude.
不実の罪で訴えられた。
He was accused of perfidy.
Compound of 不 (fu, 'not') and 実 (jitsu, 'truth, sincerity'). The kanji combination directly conveys the meaning of lacking truthfulness or fidelity.