反之【fǎnzhī】

反之 means "take the opposite case". It sits between two statements that mirror each other and introduces the second. 之 points back to what was just said, so 反之 is "reverse that". It belongs to essays, reports and textbooks.

Often the first half is a condition, and 反之 stands for "if not" – the reader fills in the negated condition. A semicolon or full stop usually comes before 反之 and a comma after it.

反之亦然

反之亦然 is "and vice versa". It closes the sentence instead of opening a new clause.

Not "on the contrary"

反之 sets up a second case. It can't correct a wrong expectation about the same case – that is 反而, or 相反 at the start of a sentence.

• × 他没有生气，反之很高兴。 → 他没有生气，反而很高兴。
• × 我以为他会走，反之他留下来了。 → 我以为他会走，没想到他留下来了。