- 自以为是 [zì yǐ wéi shì]
- be opinionated; be self-righteous; believe sth. to be correct opinionately; bumptious; claim infallibility presumptuously; consider oneself always in the right; have a firm belief in one's own opinions; opinionatedly believe sth. to be correct; regard oneself as infallible; stuffy; think oneself right
She rather fancies herself as a singer.
You're very full of yourself today, I must say.