Roughly speaking is a phrase that is commonly used when giving an estimation or approximation. There are many synonyms for this phrase that one can use to add some variation to their language. Some of the synonyms for roughly speaking include in broad terms, generally speaking, more or less, approximately, roughly, about, almost, nearly, close to, and in a ballpark. These phrases can be used interchangeably depending on the context and the degree of accuracy required. It's always important to remember to use these phrases with caution, as they don't provide a precise figure, but rather an estimate that could vary.