The phrase "holus bolus" is a term used to describe something in its entirety, all at once, or without reservation. While it can be difficult to find a direct synonym for this phrase, there are a few phrases that come close in meaning. For example, you could use the phrase "all at once" or "in one go" to convey the sense of encompassing completeness that is present in "holus bolus." Another phrase that can work as a synonym is "lock, stock, and barrel," which refers to the entirety of something, rather than just a part or aspect of it. Regardless of which phrase you use, each one conveys a sense of totality and inclusion that makes "holus bolus" such a useful phrase.