Man entering skilfully and in pugnacious manner (9)
I believe the answer is:
Here is my best explanation:
'in pugnacious manner' is the definition.
(pugnacious means argumentative or combative)
'man entering skilfully' is the wordplay.
'man' becomes 'ian' (man's name).
'entering' means one lot of letters goes inside another.
'skilfully' becomes 'deftly'.
'ian' going into 'deftly' is 'DEFIANTLY'.
'and' acts as a link.