Tough guy going round concealing dread (8)
I believe the answer is:
gangster
'tough' is the definition.
(thesaurus)
'guy going round concealing dread' is the wordplay.
'guy going round' becomes 'ger' (I can't justify this - if you can you should give a lot more credence to this answer).
'concealing' is an insertion indicator.
'dread' becomes 'angst' (I've seen this before).
'ger' placed around 'angst' is 'GANGSTER'.
Can you help me to learn more?
(Other definitions for gangster that I've seen before include "Villain" , "Mafia man" , "Member of a mob like Al Capone" , "One of a group of violent criminals" , "Member of criminal mob" .)