The antonyms for the phrase "spit up on" can be words like admire, compliment, applaud, embrace, endorse, exalt, extol, flatter, glorify, praise, venerate, and honor. These words bring out the positive connotation of the phrase and represent favorable feedback. Instead of spitting up on someone, one should commend them for their efforts or skills. A kind and positive approach will always help maintain healthy relationships with others. We should always strive to uplift people and celebrate their achievements rather than putting them down. Hence, using antonyms for "spit up on" is a better way to boost someone's morale and make them feel good.