What is the legal term for a thing that can be a felony or misdemeanor?

A "wobbler" is an offense that may be prosecuted as a felony or as a misdemeanor. An offense that was prosecuted as a felony may also be downgraded to a misdemeanor at the time of sentencing. This occurs when statutes authorize judges to punish offenders as either misdemeanants or felony offenders. Depending on the circumstances, you may not need a lawyer for something like a traffic ticket case. But for the overwhelming majority of criminal cases, using an attorney is the way to go.

Source: NOLO