Weight – worry (6)
I believe the answer is:
stress
I believe this clue is a double definition.
'weight' is the first definition.
(thesaurus)
'worry' is the second definition.
(I've seen this before)
(Other definitions for stress that I've seen before include "'Worry, pressure (6)'" , "Dwell on" , "possible excuse for sickie?" , "what causes tension" , "Tension - accent" .)