Groucho's prop is somewhat tragicomic on reflection (5)
I believe the answer is:
cigar
'groucho's prop' is the definition.
(I've seen this in another clue)
'somewhat tragicomic on reflection' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'on reflection' says the letters should be written in reverse.
'ragic' is hidden within 'tragicomic'.
'ragic' back-to-front is 'CIGAR'.
'is' acts as a link.
(Other definitions for cigar that I've seen before include "Havana, for example" , "A real smoke!" , "Roll of cured tobacco" , "Tobacco product" , "Eg, Havana, panatella" .)