If someone is called a "ham," it means they tend to be a showy or exaggerated performer. They might act in an overly dramatic or theatrical way, often like a stereotypical actor who overacts. This term can also describe someone who enjoys being the center of attention and entertaining others, often with playful or exaggerated behavior. Essentially, a "ham" is someone who likes to perform and may behave in a way that is deliberately attention-grabbing or theatrical. This can apply in casual contexts for people who are playful and like to make others laugh or in more formal ones like acting where over-the- top performances happen.

Additionally, "ham" has other meanings unrelated to personality, such as a cut of meat or an acronym (H.A.M. - hard as a motherfucker), but in everyday speech referring to a person, it usually points to the theatrical or attention-seeking behavior.