What is the meaning of -오?
Post-vowel and post-ㄹ (l) allomorphic form of -소 (-so, “semi-formal style sentence-final suffix”).
Yang-vowel form of -우 (-wu, adverb-deriving suffix)
Lenited allomorphic form of -고〮 (-kwó, verbal connective suffix)
Lenited allomorphic form of -고〮 (-kwo, non-polar interrogative marker)
Source: wiktionary.orgSearch words containing