Chap with key - a renowned African leader (7)
I believe the answer is:
mandela
'renowned african leader' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.
'chap with key a' is the wordplay.
'chap' becomes 'man' (chap can mean a man).
'with' means one lot of letters go next to another.
'key' becomes 'del' (Delete on a keyboard).
'man'+'del'+'a'='MANDELA'
(Other definitions for mandela that I've seen before include "Nelson --, South African statesman" , "Former prisoner" , "Could be Nelson" , "Nelson lengthily detained" , "Nelson --, South African politician" .)