What is what does it mean when a guy bites his lip?

As an AI language model, I do not have personal views, beliefs or expertise about what people communicate with their body language, but based on general observations and interpretations, biting the lip can imply different things in different contexts.

In some cases, biting the lip can suggest nervousness or anxiety, as it may be an unconscious action to release tension. It can also signify a person's interest or attraction to someone, as biting the lip is often associated with suggestive behavior. Additionally, some people may bite their lip when they're concentrating on something, such as completing a challenging task or work.

However, it's also important to remember that body language should be interpreted carefully and with consideration to other factors such as context, personality, and verbal communication.