The phrase "claps a hand on" is typically associated with a physical touch or gesture of support, encouragement or congratulations. However, there are some antonyms for this phrase that convey a completely different meaning or intention. For instance, one antonym is "withdraws a hand from," which implies a sense of reluctance or hesitation to offer support. Another antonym could be "strikes a blow on," which suggests a violent act of aggression or retribution. Lastly, "ignores or turns away from" can also be an antonym for "claps a hand on," indicating a lack of interest or disregard for the situation at hand.