One more on earth, maybe
I believe the answer is:
another
'one more' is the definition.
(I've seen this before)
'on earth maybe' is the wordplay.
'maybe' is an anagram indicator.
'on'+'earth'='onearth'
'onearth' is an anagram of 'ANOTHER'.
(Other definitions for another that I've seen before include "On earth (anag.)" , "Additional: alternative" , "Player or person not yet named or selected" , "A different one" , "Somebody else" .)