The phrase "in a quiver" refers to a state of nervousness or excitement. There are many synonyms for this phrase that can be used to express a similar feeling. Some alternatives include "trembling," "shaking," "quaking," "quivering," "shivering," "shuddering," "flinching," and "startled." Each of these words can be used to convey a sense of anxiety or anticipation, and can be used in a variety of contexts. Whether you are describing an athlete before a big game, a student preparing for an exam, or a person facing a difficult challenge, there are many ways to express the feeling of being in a quiver.