The phrase "quickness of perception" refers to the ability to quickly understand and interpret information. There are many synonyms for this phrase, including sharpness, acuity, discernment, insight, intuition, sensitivity, and perceptiveness. These words all imply a quick and accurate understanding of information, but each one has its own nuance. For example, "sharpness" suggests a keenness in noticing details, while "insight" implies a deeper understanding of a situation. "Sensitivity" emphasizes the ability to pick up on subtle cues, while "perceptiveness" refers to the overall ability to grasp a situation quickly. Choosing the right synonym for "quickness of perception" depends on the context of the situation and the specific characteristics being described.