Ingenuous

Mary is an ingenuous student.

Some secret sorrow, or the brooding spirit of some moody passion, had quenched the light and ingenuous vivacity of youth.

"Do you mean to say you didn't leave your wife for another woman?" "Of course not." "On your word of honour?" I don't know why I asked for that. It was very ingenuous of me.

The apparent contradictions in his behaviour should therefore be discounted as ingenuous attempts to extricate himself from the consequences of an intellectual position which he once adopted but was never really his by intimate conviction.

[…] Semitic agitation by stating 'the truth' in terms of facts and figures, the practice of self-criticism represented a well-intended but ingenuous effort to defend Jewry against anti-Semitism.

There was nothing more I dared say. My ingenuous attempts to lie my way out of trouble had only served to get me in deeper and deeper.

[H]is Grace’s Man at his club, in company doubtless with other Men of equal social rank, talks over his master’s character and affairs with the ingenuous truthfulness which befits gentlemen who are met together in confidence.