Some common British slang words include "mate," "bollocks," "ace" and "bloody." British slang is quite different from the media-publicized American slang most people are familiar with. As any language, British slang is constantly evolving and it may vary from city to city.
"Mate" is perhaps one of the most commonly used slang terms in the United Kingdom, and it is also widely known in other parts of the world. It is an affectionate term indicating a friend, and it can be understood as the British version of American terms such as "buddy" or "pal."
"Bollocks" is another widely known slang term, and it has multiple uses in the British language. It is often used to indicate disconcert or distress, such as in the exclamation "Oh bollocks!" Alternatively, British speakers may elect to use it to express scornful disbelief, in which case the term may be best equated to the American "bullshit."
"Ace" is one of the most easily understood slang terms, as it finds an exact correspondence in the American "awesome." It can also be substituted by "brill," a synonymous slang term and short for "brilliant."
Lastly, "bloody" is an extremely versatile word in British English. It can be used to signify surprise in expressions such as "bloody hell," or to add emphasis to almost anything, for example in expressions such as "bloody awful," "bloody mad," and so on.