Used when the speaker is unsure or vague about what something is, often implying 'something or other' or 'some kind of thing'. Can appear in questions or statements expressing uncertainty.
He seemed to want to say something or other.
It seems something (or other) happened.
Mixed kanji-kana spelling, sometimes used for clarity or emphasis.
Compound of 何事 (nanigoto, 'what thing') + か (ka, question particle). The combination yields a meaning of 'something or other'.