Putatively is an adverb that is often used to describe something that is believed or assumed to be true, but without proof or confirmation. There are a number of other words that can be used in place of putatively, depending on the context and the intended meaning. Some possible synonyms include supposedly, allegedly, purportedly, presumptively, probatively, hypothetically, and ostensively. Each of these words conveys a slightly different shade of meaning, but all serve to indicate that something is being presented as true or factual, but may not be actually proven or confirmed.