Grand relative, but looking haggard (5)
I believe the answer is:
gaunt
'haggard' is the definition.
(I know that haggard can be written as gaunt)
'grand relative' is the wordplay.
'grand' becomes 'g' (G is short for grand as in a thousand).
'relative' becomes 'aunt' (aunt is a type of relative).
'g'+'aunt'='GAUNT'
'but looking' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for gaunt that I've seen before include "place associated with Edward III's son" , "Hence John" , "Hollow-eyed, skinny" , "Grim" , "Very thin, cadaverous" .)