Grand aunt looks haggard (5)
I believe the answer is:
gaunt
'haggard' is the definition.
(I know that haggard can be written as gaunt)
'grand aunt' is the wordplay.
'grand' becomes 'g' (G is short for grand as in a thousand).
'g'+'aunt'='GAUNT'
'looks' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for gaunt that I've seen before include "Very thin, cadaverous" , "Very thin especially from disease or hunger" , "place associated with Edward III's son" , "forlorn" , "Very slight" .)