Mostly well-mannered, endlessly nice and ordinary government minister, perhaps (8)
I believe the answer is:
politico
'government minister perhaps' is the definition.
I can't tell whether this defines the answer.
'mostly well-mannered endlessly nice and ordinary' is the wordplay.
'mostly' means to remove the last letter.
'well mannered' becomes 'polite' (I've seen this before).
'endlessly' means to look at the middle letters (the ends of the words are removed).
'and' says to put letters next to each other.
'ordinary' becomes 'o' (abbreviation e.g. O-Levels).
The middle of 'nice' is 'ic'.
'polite' with its final letter taken off is 'polit'.
'polit'+'ic'+'o'='POLITICO'
Can you help me to learn more?
(Other definitions for politico that I've seen before include "Party type" , "Person with party views (colloq.)" , "Party man" , "MP, for instance" , "statesman" .)