At the very pinnacle of bliss; euphoric; on a cloud: She came back home and he's on cloud nine(1950s+)
Idioms and Phrases with on cloud nine
on cloud nine
Blissfully happy, as in Ever since he proposed to her, her parents have been on cloud nine. The exact allusion of nine in this term is unclear, and different figures, especially seven (perhaps alluding to seventh heaven), are sometimes substituted. [ ; mid-1900s ]