まさか

まさか is an adverb used to express strong disbelief, surprise, or the feeling that something is impossible or completely unexpected. It conveys the sense of "no way," "surely not," "I can't believe," or "I never dreamed that…"

Expressing disbelief – "No way!" / "Surely not"

まさか can be used on its own as an exclamation to express shock or disbelief when hearing something unexpected.

まさか～とは思わなかった – "I never dreamed that…"

Combined with とはおもわなかった思わなかった or とはおもいませんでした思いませんでした, まさか expresses that something was completely beyond one's expectations.

まさか～ないだろう / ～ないでしょう – "Surely… won't / can't"

When paired with a negative predicate and だろう or でしょう, まさか expresses the speaker's belief that something is highly unlikely or impossible.

まさか～わけがない – "There's no way that…"

Combined with わけがない, まさか strongly emphasizes impossibility.

Nuances

まさか inherently carries a tone of surprise or emotional reaction. It is used when the speaker encounters – or imagines – a situation that defies their expectations. It can appear in both casual and polite speech. When used at the start of a sentence with a questioning tone, it often implies "Don't tell me that…" or "It can't be that…"