The term "more frost-bound" implies that something is even more cold and icy than it already is. Antonyms for this phrase, therefore, would be words that suggest warmth and lack of frostiness. Some examples of antonyms for "more frost-bound" include "balmy," "mild," "temperate," "tropical," and "warm." Each of these words evokes a sense of warmth, softness, and gentleness. They represent the polar opposite of the cold and harsh nature of a frost-bound environment. Using these antonyms in place of "more frost-bound" can help add variety and depth to your writing, especially when attempting to convey warmth and positivity.