Roberto won 5 million dollars in the lottery. he secretly gave 2 million dollars to a homeless shelter without anyone knowing who gave the money. roberto's behavior can be described as

anonymous. When a person does some action which can not be linked to him in any way, it is considered anonymous. Since in the example nobody knew who donated the money, such behavior fits the description of 'anonymous' very well. If there was anyone at the shelter who knew that the winner of the lottery donated the money, it would not be called anonymous.