Sign of laughter by Republican glutton? (9)
I believe the answer is:
harbinger
'sign' is the definition.
(harbinger is a kind of sign)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for harbinger that I've seen before include "Precursor" , "sign of things to come" , "Herald - forerunner" , "Early sign" , "One giving advance warning" .)