Regularly taking gun to protest, turned persuasive (6)
I believe the answer is:
strong
'persuasive' is the definition.
(thesaurus)
'regularly taking gun to protest turned' is the wordplay.
'regularly taking' means one should take alternating letters.
'turned' says the letters should be written backwards.
'gun'+'to'+'protest'='guntoprotest'
The alternate letters of 'guntoprotest' are 'gnorts'.
'gnorts' in reverse letter order is 'STRONG'.
(Other definitions for strong that I've seen before include "Powerful; highly alcoholic" , "Resilient" , "Robust and muscular" , "Mighty, powerful" , "Able to withstand attack" .)