Relative bringing Ghanaian diplomat up (5)
I believe the answer is:
nanna
'relative' is the definition.
(I know that nanna is a type of relative)
'ghanaian diplomat up' is the wordplay.
'ghanaian diplomat' becomes 'Annan' (former UN Secretary-General Kofi Annan).
'up' is a reversal indicator (in down clue: letters go upwards).
'annan' back-to-front is 'NANNA'.
'bringing' acts as a link.
(Other definitions for nanna that I've seen before include "Mother's mother?" , "Senior woman" , "Older lady" , "Grandma" , "old Indian currency" .)