Corpsing is a term used in theatre and film to refer to a performer who breaks character by laughing or smiling during a scene. It can be embarrassing for the performer and spoil the audience's suspension of disbelief. Here are some synonyms for corpsing: breaking character, losing composure, cracking up, losing it, giggling, chuckling, sniggering, snickering, tittering, and hysterics. While corpsing can be a setback for a performance, it's important to remember that actors are human and sometimes laughter can be infectious. The key is to try to regain composure and get back in character as quickly as possible.