The term "Blue Flame" refers to a hot, intense, and powerful source of light or heat. Some possible antonyms for this term could be "cool," "calm," "mild," "gentle," or "soft." These words suggest a much less intense or aggressive level of heat or light. Other possible antonyms might include "dim," "faint," "weak," "dull," or "pale." These words indicate a lack of intensity or brightness altogether. Overall, antonyms for the term "Blue Flame" convey a sense of calmness, softness, and mildness, in contrast to the powerful energy typically associated with this term.