The phrase "cause mirth" refers to something that makes people laugh or feel joyful. There are many synonyms for this phrase, including "entertain," "amuse," "delight," "ticklesome," and "humorous." Other synonyms for "cause mirth" may include "cheerful," "lighthearted," "jocund," and "gleeful." Whatever term is used, the goal is to convey the idea of something that brings enjoyment and laughter to those who experience it. Whether it's a funny joke, a playful prank, or a humorous story, causing mirth is a wonderful way to lift the spirits and bring happiness into the world.