Unsociable type, single, welcomed by political extremes (5)
I believe the answer is:
loner
'unsociable type' is the definition.
(I've seen this in another clue)
'single welcomed by political extremes' is the wordplay.
'single' becomes 'lone' (synonyms).
'welcomed by political extremes' becomes 'r' (I am not sure about this - if you are sure you should believe this answer much more).
'lone'+'r'='LONER'
Can you help me to learn more?
(Other definitions for loner that I've seen before include "Individualist" , "Person who prefers his own company" , "Unsociable person" , "One preferring to act individually" , "Introvert" .)