Verbseoul.
하다 verb (adj)
지루하다jiruhadato be boring, tedious, dull

To say to be boring, tedious, dull politely in the present tense, use 지루해요 (chee-roo-hae-yoh). Below is the full conjugation of 지루하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
지루해
chee-roo-hae
지루해요
chee-roo-hae-yoh
지루합니다
chee-roo-hahm-nee-dah
Past
지루했어
chee-roo-hae-ssuh
지루했어요
chee-roo-hae-ssuh-yoh
지루했습니다
chee-roo-hae-sseum-nee-dah
Future
지루할 거야
chee-roo-hahl- -guh-yah
지루할 거예요
chee-roo-hahl- -guh-yae-yoh
지루할 겁니다
chee-roo-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
지루하세요
chee-roo-hah-sae-yoh
Suggestion / Let's Polite (요)
지루해요
chee-roo-hae-yoh
Question Polite (요)
지루해요?
chee-roo-hae-yoh-?
Connective “and” — (고)
지루하고
chee-roo-hah-goh
Conditional “if” — (면)
지루하면
chee-roo-hah-myuhn
Noun form — (기)
지루함
chee-roo-hahm