若无其事 act as if nothing were on one's mind; (appeared) as if nothing had happened; as if nothing had occurred; as if nothing were wrong; carry it off well; (went off) just as if nothing at all had happened
殆无其匹 there is no equal.; there is scarcely any equal
世无其匹 unrivalled in the world; one's equal is not found on earth
旁若无人 act as if there was no one else present -- self-assured or supercilious; act as if no one was nearby -- an unwarranted assumption of airs; act or talk in a supercilious manner; as if nobody else besides oneself counts; as if nobody were near him; as if no one was about; as if there was nobody present; as though no one were nearby; completely informal; have no regard for others
若有若无 not much, if any; faintly discernible; intangible; vague
视若无睹 turn a blind eye to; take no notice [heed] of what has been seen; shut one's eyes to; be undisturbed by what one has seen; give sb. the go-by 他脱下帽子, 正想和她打招呼, 但她却视若无睹, 扬长而去。 he raised his hat and was about to speak to her, but she gave him the go-by and kept on walking