The term "up rears" can be interpreted in different ways, but one possible synonym for it is "rises up." This phrase evokes the image of something or someone standing tall or ascending from a low position. Other synonyms for "up rears" might include "lifts," "propels," "boosts," or "elevates." Each of these words suggests some kind of upward motion or force, whether physical or metaphorical. Depending on the context, "up rears" could also be synonymous with "jumps," "leaps," "springs," or "bursts," indicating a sudden or energetic movement. Ultimately, the choice of synonym will depend on the precise meaning and tone of the original phrase.