The phrase "more white-hot" refers to something that is extremely hot or intense. Antonyms for this phrase could include "cold," "cool," "chilly," or "frigid," all of which indicate a lack of heat or intensity. Other antonyms could include "mild," "moderate," "temperate," or "lukewarm," which suggest a level of heat or intensity that is lower than that suggested by "more white-hot." These antonyms could be useful in contexts where a writer or speaker wants to indicate a cooling off period, a decrease in intensity, or a shift away from extreme emotions or actions.