Wage war ultimately with extraterrestrial visitor? (7)
I believe the answer is:
incomer
'extraterrestrial visitor?' is the definition.
'incomer' can be an answer for 'visitor?' (thesaurus). I am not certain of the 'extraterrestrial' bit.
'wage war ultimately' is the wordplay.
'wage' becomes 'income' (I've seen this before).
'ultimately' says to take the final letters.
The final letter of 'war' is 'r'.
'income'+'r'='INCOMER'
'with' is the link.
Can you help me to learn more?
(Other definitions for incomer that I've seen before include "Perhaps asylum seeker" , "Recent arrival" , "No native" , "Immigrant" , "New resident where he was not born" .)