Alleged

[Vania]

An action or person, stated without [proof].

Girl- [my bff] said she saw you cheating!
Boy- [allegedly] cheating! Wheres her proof!?!

[Greta]

When you know something is true, but to [cover] it up you say it is [alleged] or [allegedly] true

[Dave Paprocki]

Said, without proof, to have taken place or to have a specified illegal or undesirable quality.

[Tina]

said or thought by some people to be the stated bad or illegal thing, although you have no proof:

[Sommer]

(of an incident or a person) said, without proof, to have taken place or to have a specified illegal or undesirable quality.