The phrase "give the come-on" typically refers to flirting or making advances towards someone in a subtle or suggestive way. However, depending on the context, there are various antonyms that can be used to express the opposite of this behavior, such as "ignore", "avoid", "reject", "disinterest", or "remain aloof". These antonyms convey a sense of disengagement or indifference towards the other person or situation, indicating that the speaker does not want to pursue a romantic or sexual relationship. Ultimately, the choice of antonym will depend on the specific context and desired tone of the conversation.