do something without right or permission
presumptuous - bold
To be ‘presumptuous’ is to say or do something that goes beyond what you have a right or authority to do. It is not a question of legality, it is more related to good manners and social norms. In other words, to be presumptuous is a sign of a lack of respect and excessive confidence, if not arrogance.
Person A: “Jane left work early today. She said you wouldn’t mind.” Person B: “That was rather presumptuous of her.”
There is as yet no clear evidence to support your finding, yet you are presumptuously stating it as a fact.
Person A: “Would your team be willing to work this weekend to complete the order?” Person B: “It would be presumptuous of me to answer that without consulting them first.”