infrequent
/(ˌ)in-ˈfrē-kwənt/
adjective
seldom happening or occurring : rare
placed or occurring at wide intervals in space or time
infrequent uncommon scarce rare sporadic mean not common or abundant. infrequent implies occurrence at wide intervals in space or time. uncommon suggests a frequency below normal expectation.
idiom
occurring rather often : common
Problems with the network have become a not infrequent occurrence.