What is a tosser?

The term "tosser" is a slang term used in British English to refer to someone who is arrogant, self-absorbed, or generally unpleasant. It can also be used as an insult to suggest that someone is foolish or idiotic.

In Australian English, the term "tosser" can also refer to someone who masturbates.

Overall, calling someone a "tosser" is considered to be a rude and offensive insult. It is important to be mindful of the context in which this term is used and to be respectful towards others in communication.