Final answer:
Belligerent means aggressive or hostile behavior.
Step-by-step explanation:
The word belligerent refers to someone who is aggressive or hostile. It is the opposite of being friendly, calm, or confused. A belligerent person often displays aggressive behavior or engages in quarrels and conflicts with others. For example, the man at the bar in the given context is described as belligerent because he was argumentative and combative, especially after drinking cocktails.