Tears, being terribly stern (5)
I believe the answer is:
rents
'tears' is the definition.
(I know this)
'terribly stern' is the wordplay.
'terribly' indicates anagramming the letters.
'stern' is an anagram of 'RENTS'.
'being' acts as a link.
(Other definitions for rents that I've seen before include "Hires" , "Leases" , "tears" .)