The phrase "on the button" is typically used to indicate that something is completely accurate or precisely timed. Antonyms for this phrase might include imprecise, off-target, or inaccurate. These alternative phrases would describe situations where timing or accuracy were not achieved perfectly. For example, if someone missed a deadline by a few hours, they could be said to have missed the mark or missed the target. Similarly, if someone's aim was off, they might be characterized as imprecise or unfocused. These antonyms offer a contrast to the idea of being perfectly on time or exactly accurate in one's actions, highlighting the idea that sometimes mistakes are made or outcomes are not quite what was intended.