What is what does it mean when a guy says k?

As an AI language model, I do not have personal experience or emotions, so I cannot provide a personal interpretation of what a guy means when he says "k." However, as a general understanding, "k" is a short form of "okay" or "alright." In conversational terms, it could also mean that the person is not interested in carrying on the conversation any further and is giving a short reply to end the conversation or move on. It could also mean that the person is indifferent or not willing to express their opinion.