Poetic or literary pronoun for 'self'; used in elevated or reflective contexts, not in everyday conversation.
It is important to know oneself.
Humble first-person pronoun used mainly by men in formal or self-deprecating contexts; can sound old-fashioned or stiff.
It was due to my own inexperience that I caused you trouble.
Derogatory second-person pronoun used to address someone with contempt or anger; often heard in confrontational or rough speech.
You bastard, how dare you deceive me!
Adverbial use meaning 'by oneself' or 'of its own accord'; often appears in set phrases like 己から (of one's own will).
He took on that task of his own accord.
damn!; blast!
Interjection expressing anger, frustration, or chagrin; used in dramatic or old-fashioned speech, similar to 'damn it!'.
Damn, I lost again!