Worried after reversal of gun control (8)
I believe the answer is:
regulate
'control' is the definition.
(thesaurus)
'worried after reversal of gun' is the wordplay.
'worried' becomes 'ate' (I've seen this before).
'after' says to put letters next to each other.
'reversal of' says the letters should be written in reverse.
'gun' becomes 'luger' (type of pistol).
'luger' back-to-front is 'regul'.
'ate' put after 'regul' is 'REGULATE'.
(Other definitions for regulate that I've seen before include "Ate gruel (anag.)" , "exercise control" , "Bring order" , "Control or direct by means of rules and procedures" , "Control, manage" .)