The antonyms for the term 'celestial being' may vary depending upon the context it's being used. If we consider celestial being as a creature or entity that belongs to the heavens or is divine, then its antonyms could be earthly being, mortal or human being. Conversely, if celestial being implies evil or demonic entities, then its antonyms could be angelic beings, divine entities or celestial beings. Some may argue that there is no exact opposite for celestial being, as its meaning is broad and abstract. Instead, it can be seen as a concept that stands on its own without any concrete antonyms.