Worry, return bag to Israel (7)
I believe the answer is:
tension
'worry' is the definition.
(thesaurus)
'return bag to israel' is the wordplay.
'return' shows that the letters should be reversed in order.
'bag' becomes 'net' (I've seen this in other clues).
'to israel' becomes 'sion' (I've seen this in other clues).
'net' back-to-front is 'ten'.
'ten'+'sion'='TENSION'
(Other definitions for tension that I've seen before include "Strained condition" , "Stress, tautness" , "State of strain or suspense" , "Mental or emotional strain" , "Assay" .)