Offensive English boxer starting to nettle in tirade (9)
I believe the answer is:
repugnant
'offensive' is the definition.
(similar in meaning)
'english boxer starting to nettle in tirade' is the wordplay.
'english' becomes 'e' (abbreviation).
'boxer' becomes 'pug' (short for pugilist - term for boxer).
'starting to' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'tirade' becomes 'rant' (I've seen this before).
The first letter of 'nettle' is 'n'.
'e'+'pug'+'n'='epugn'
'epugn' put inside 'rant' is 'REPUGNANT'.
(Other definitions for repugnant that I've seen before include "Nasty" , "Unacceptable" , "Offensive to the mind" , "revolting" , "Abhorrent" .)