Verbseoul.
regular
망치다mangchidato spoil

To say to spoil politely in the present tense, use 망쳐요 (mahng-chyuh-yoh). Below is the full conjugation of 망치다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
망쳐
mahng-chyuh
망쳐요
mahng-chyuh-yoh
망칩니다
mahng-cheem-nee-dah
Past
망쳤어
mahng-chyuh-ssuh
망쳤어요
mahng-chyuh-ssuh-yoh
망쳤습니다
mahng-chyuh-sseum-nee-dah
Future
망칠 거야
mahng-cheel- -guh-yah
망칠 거예요
mahng-cheel- -guh-yae-yoh
망칠 겁니다
mahng-cheel- -guhm-nee-dah

Other useful forms

Command Polite (세요)
망치세요
mahng-chee-sae-yoh
Suggestion / Let's Polite (요)
망쳐요
mahng-chyuh-yoh
Question Polite (요)
망쳐요?
mahng-chyuh-yoh-?
Connective “and” — (고)
망치고
mahng-chee-goh
Conditional “if” — (면)
망치면
mahng-chee-myuhn
Noun form — (기)
망침
mahng-cheem