The term INFREQUENCY refers to the state of being infrequent or occurring rarely. This can be further defined by two related terms, RARENESS (8 letters) and SELDOMNESS (10 letters). RARENESS is defined as the quality or state of being rare, while SELDOMNESS is defined as the quality or state of being seldom or occurring infrequently. Together, these terms describe the concept of INFREQUENCY, which is the state of being infrequent or occurring rarely.