Learn Hardcore Korean: mureul masyeoyo.

을 is the object-marking particle. It tells us that 물 (water) is the direct object of the verb 마셔요 (to drink). When the noun ends in a consonant (like 물), you attach 을; if it ended in a vowel, you’d use 를.

Why is 마시다 conjugated as 마셔요 instead of 마십니다?

Korean verbs follow different politeness levels. 마셔요 is the present-tense polite style (often called 해요체), formed by dropping –다 from 마시다 and adding –아요/–어요: 마시 + 어요 → 마셔요.
마십니다 is the present tense in the formal polite style (합쇼체), used in announcements or very formal situations.

What level of politeness does 마셔요 represent?

마셔요 is polite but not overly formal. It’s the standard polite speech used in everyday conversations with people you’re not extremely close to—co-workers, classmates, or strangers. It’s softer than the plain style (마신다) and less rigid than the formal style (마십니다).

Why is there no subject in 물을 마셔요?

Korean often drops the subject when it’s understood from context. If you and your listener both know you’re talking about yourself (or someone else), you can omit , , etc. This zero-pronoun usage is very common in Korean.