Mean lad upset old statesman (7)
I believe the answer is:
mandela
'old statesman' is the definition.
'Mandela' can be an answer for 'statesman' (Nelson Mandela). I am not certain of the 'old' bit.
'mean lad upset' is the wordplay.
'upset' is an anagram indicator.
'mean'+'lad'='meanlad'
'meanlad' with letters rearranged gives 'MANDELA'.
Can you help me to learn more?
(Other definitions for mandela that I've seen before include "Former prisoner" , "Nelson lengthily detained" , "South African president, 1994-99" , "Former president of South Africa" , "Nelson --, South African politician" .)