Sentence:  Sitting on the edge of the stage at the show's end, draped in a flag and singing You Need Me, a <WSD>bullish</WSD> screw-you written when he was 15, he didn't look much like a man still plagued by nerves over headlining Glastonbury. 
Meaning of the word marked with <WSD> tags:  Aggressively self-confident or assertive; bullheaded