What does "hardly" imply about the frequency of an event?

The term "hardly" indicates a low frequency of occurrence, suggesting that an event takes place very infrequently or not at all. When someone says something happens "hardly" ever, it communicates a sense that the event is almost negligible in terms of its occurrence. Thus, the implication aligns closely with the meaning of "rarely" — which is an event that does not happen often. This makes it the most appropriate choice to convey the intended idea of low frequency associated with the term "hardly."