(the reflexive form of one one 的反身形式 used as the object of a verb or preposition when ‘one’ is the subject of the verb or is understood as the subject （one 作動詞的主語時，oneself 作動詞或介詞的賓語）自己，自身 used to emphasize one （用以強調 one）親自，自己 One and oneself are very formal words and now sound old-fashioned. It is much more usual to use you and yourself for referring to people in general and I and myself when the speaker is referring to himself or herself.
Idioms
be oneself
(all) by oneself
alone; without anyone else （某人）獨自，單獨 Meditating by oneself is also beneficial. 自己冥想也是有益的。
without help （某人）獨立地 Trying to manage all these changes by oneself is no good. 試圖自己管理所有這些變化是沒有好處的。
(all) to oneself
not shared with anyone 獨享的；獨自擁有的 Performance, even privately to oneself, is an art. 表演，哪怕是私下對自己，都是一門藝術。