Give support to the final part or the south-east (7)
I believe the answer is:
endorse
'give support to' is the definition.
(I've seen this in another clue)
'final part or the south-east' is the wordplay.
'final part' becomes 'end' (I've seen this before).
'the south east' becomes 'SE' (abbreviation).
'end'+'or'+'se'='ENDORSE'
'the' acts as a link.
(Other definitions for endorse that I've seen before include "Support; sanction" , "Docket" , "Back, sanction" , "Add one's authority to" , "Rubber-stamp" .)