Offensive, a course inspiring thuggery primarily (6)
I believe the answer is:
attack
'offensive' is the definition.
('attack' can be similar in meaning to 'offensive')
'a course inspiring thuggery primarily' is the wordplay.
'course' becomes 'tack' (I've seen this before**).
'inspiring' indicates putting letters inside.
'primarily' suggests taking the first letters.
The first letter of 'thuggery' is 't'.
'tack' enclosing 't' is 'ttack'.
'a'+'ttack'='ATTACK'
(Other definitions for attack that I've seen before include "Fiercely criticise" , "Invade; vilify" , "Assault or criticise violently" , "storm" , "attempt at seizure" .)