crimen

Crimen, criminis is third declension neuter, so nominative and accusative are both crimen and the plural is crimina. It is related to cerno, "to sift, decide", and its oldest sense is the accusation rather than the deed.

That is the false friend to watch. In Cicero a crimen is usually the charge laid, true or false, and a man can be attacked with crimina falsa; the act itself is scelus, facinus or maleficium. The modern meaning creeps in through late Latin and is standard by the medieval period, which is where most of this corpus sits, so read the date before you translate. The verb criminor means to accuse, not to offend, and English recrimination preserves that older shape exactly.