Star in hurry loses hour by chance (8)
I believe the answer is:
asterisk
'chance' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'star in hurry loses hour by' is the wordplay.
'star in' becomes 'risk' (I can't justify this - if you can you should give a lot more credence to this answer).
'hurry' becomes 'haste' (haste is hurrying or rushing).
'loses' suggests deleting specific letters.
'hour' becomes 'h'.
'by' is a charade indicator (letters next to each other).
'haste' with 'h' taken out is 'aste'.
'risk' after 'aste' is 'ASTERISK'.
Can you help me to learn more?
(Other definitions for asterisk that I've seen before include "Star-shaped character used in printing" , "Sarkiest (Anag)" , "Star on a page" , "Footnote marker" , "Printed star" .)