Supposedly
Part of speech: adverb
Definition: As a matter of supposition; in the beliefs or according to the claims of some people.
Example sentence: The most important funder of the British Brexit campaign had odd Russian contacts. So did some cabinet ministers in Poland's supposedly anti-Russian, hard-right government, elected after a campaign marked by online disinformation in 2015.
Purportedly
Part of speech: adverb
Definition: supposedly, putatively or reputedly
