Stress set in on moving (7)
I believe the answer is:
tension
'stress' is the definition.
(I know that stress can be written as tension)
'set in on moving' is the wordplay.
'moving' is an anagram indicator.
'set'+'in'+'on'='setinon'
'setinon' with letters rearranged gives 'TENSION'.
(Other definitions for tension that I've seen before include "Uneasiness" , "Intones (anag) - stress" , "Anxiety" , "Stress, tautness" , "Mental or emotional strain" .)