Which term refers to serious crimes punishable by significant penalties?

The term that refers to serious crimes punishable by significant penalties is "felony." Felonies are typically defined as offenses that are more severe than misdemeanors and carry heavier penalties, which can include imprisonment for over a year, large fines, or both. These types of crimes often have long-lasting impacts on an individual's life, including potential loss of civil rights, such as voting and gun ownership.

In contrast, misdemeanors are considered less serious offenses, generally incur shorter jail sentences (typically less than one year), and often result in fines or community service. Transgressions are violations of a law or command that may not necessarily refer to a specific category of crime, whereas infractions are minor violations typically punishable by fines and do not carry imprisonment. Therefore, understanding the distinction in severity and consequences associated with these terms clarifies why "felony" is the correct choice when discussing serious crimes with significant penalties.