It’s rotten being short of money (4)
I believe the answer is:
poor
I believe this is a double definition.
'it's rotten' is the first definition.
(I've seen this before)
'short of money' is the second definition.
(thesaurus)
'being' acts as a link.
(Other definitions for poor that I've seen before include "Badly off - inferior in quality" , "Having little money or means" , "Scanty" , "Rotten" , "Of inferior standard" .)