Varsity sportsperson down in the dumps (4)
I believe the answer is:
blue
This clue is a triple definition!
'varsity sportsperson' is the first definition.
(blue can mean an Oxford or Cambridge sportsperson)
'down' is the second definition.
(both can mean sad)
'in the dumps' is the third definition.
(I've seen this in another clue)
(Other definitions for blue that I've seen before include "in Oxford, it's dark" , "Colour; obscene" , "Colour; depressed" , "and 17 World's largest mammal" , "Sad; butterfly" .)