さもないと

conjunction

otherwise; or else; if not

Used to state a negative consequence that will happen if the preceding condition is not met. Often at the beginning of a sentence.

• 急いそいでください。さもないと遅おくれますよ。

  Please hurry up. Otherwise, you'll be late.

• もっと勉べん強きょうしなさい。さもないと試し験けんに落おちるよ。

  Study harder. Or else you'll fail the exam.