몰라요 and 몰라 is the conjugated form of the verb 모르다, meaning “to not know.”

To review verb conjugation, see my lesson on conjugation.

”잘 모르겠습니다” is the formal way to say “I don’t know.” 잘 means “well,” so this translates to “I don’t know well.”

To review when to use different versions of the same phrase, see my lesson on politeness levels.