English Translation
It has ceased raining.
The root verb of 그쳤다 is 그치다. Here are some common conjugations of 그치다:
그치다 (geuchida): to stop, to cease
그쳐요 (geuchyeoyo): present tense polite form
그쳤어요 (geuchyeosseoyo): past tense polite form
그치세요 (geuchiseyo): imperative polite form
그쳐 (geuchyeo): present tense casual form
그쳤어 (geuchyeosseo): past tense casual form
그쳐라 (geuchyeora): imperative casual form