One more on Earth taken out (7)
I believe the answer is:
another
'one more' is the definition.
(I've seen this before)
'on earth taken out' is the wordplay.
'taken out' indicates an anagram.
'on'+'earth'='onearth'
'onearth' is an anagram of 'ANOTHER'.
(Other definitions for another that I've seen before include "A further (item)" , "Somebody else" , "Additional, one more" , "No heart (anag.)" , "Someone else" .)