"Brassed off" is a British slang term that means feeling fed up, annoyed, or frustrated. If you are tired of using the same old phrase, there are numerous synonyms that you can use to express your frustration without being repetitive. Some of the alternatives to "brassed off" include "displeased," "aggravated," "irritated," "exasperated," "fed up," "annoyed," "enraged," and "irate." Each of these words carries a slightly different meaning and sentiment, allowing you to tailor your message to suit the situation. Whether you're venting to a friend or writing a complaint letter, using a diverse range of synonyms can help you communicate your frustrations more effectively.