1. Contempt; scorn.
2. Neglect in performing the duties of public office.
3. (Law) Concealing, or neglecting to report or prevent, a felony or act of treason that one knew of but did not participate in.
4. Misunderstanding or misinterpretation; a misreading of a text.
Based on the wikipedia article, definition 3 is 'negative misprision', while 'positive misprision' is the actual commission of an offence (one that falls short of treason or a felony).
Etymology: Old French mesprendre, to make a mistake
"If a man grows marijuana on his farm with the intent to distribute, he commits a felony under federal law. If he builds a barbed-wire fence around the farm to prevent the felony’s discovery, he is guilty of misprision....If instead of building a fence, the farmer simply told all visitors to his farm that he was growing horsemint, not marijuana, he would likewise be guilty of misprision. Just as he built the fence to conceal the felony in the first example, in the second example, he made statements to conceal the felony."
- from this Washington Post article.