Responsibility felt by famous star to return to ring. (4)
I believe the answer is:
onus
'responsibility' is the definition.
(onus is a duty or responsibility)
'star to return to ring' is the wordplay.
'star' becomes 'sun' (the Sun is a star).
'to return' is a reversal indicator.
'to' means one lot of letters go next to another (I've seen this in other clues).
'ring' becomes 'o' (letter resembling a ring).
'sun' back-to-front is 'nus'.
'nus' after 'o' is 'ONUS'.
'felt by famous' 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 onus that I've seen before include "Weight of responsibility" , "'Burden, of proof (4)'" , "Encumbrance" , "'Burden, load (4)'" , "Capulet opponent (R&J)" .)