Supposably is often used as a synonym for the word "supposedly." However, there are other alternative terms that can be used instead of supposably to convey the same meaning. These synonyms include allegedly, supposedly, reportedly, ostensible, presumed, apparent, and putative. Each of these synonyms can be used in sentences to indicate that something is believed or assumed to be true without confirmation or proof. For instance, instead of "supposably he is rich," you can say "he is supposedly rich" or "he is allegedly rich." Generally, it's essential to note that these alternative synonyms should be used contextually to avoid ambiguity or misinterpretation.