Presentism is the application of present-day values and standards to earlier eras. It has commonly been used unfairly to pass judgment on historical figures, but recent scholarship has fortunately tended to avoid this error.
An example of presentism is the effort to remove the name of Woodrow Wilson from the campus of Princeton University, despite how he has long been one of its most revered historical figures. The reason for the movement to erase him from campus is that when he was President of the United States he excluded African Americans from civil service.
Another example is reading "the evening" in the Bible as the end of the day, instead of its beginning according to Jewish tradition, as in Genesis 1 "and the evening and the morning were the ... day". This is why in their reckoning of the religious calendar Jewish days begin at sundown. Thus the evening of Passover just before sunset preceded the day of Passover which followed the next morning; it was not the end of the day of Passover. Nisan 13 at sundown was the beginning of Nisan 14 "at twilight, between the two evenings".