The phrase "most har-har" is an informal way to describe something that is very funny or humorous. There are many synonyms for this phrase that can be used interchangeably, such as "hilarious," "side-splitting," "uproarious," "laugh-out-loud," "gut-busting," "comical," "amusing," "funny," "witty," and "droll." Each of these words adds a unique flavor to the description of something that is "most har-har." Depending on the context and audience, one synonym may be more appropriate than another. However, all of these words have one thing in common - they describe something that is sure to elicit a good laugh.