Word family noun frequency ≠ infrequency adjective frequent ≠ infrequent verb frequent adverb frequently ≠ infrequently
From Longman Dictionary of Contemporary Englishinfrequentlyin‧fre‧quent‧ly /ɪnˈfriːkwəntli/ adverb 1 not often SYN rarely OPP frequently Jeremy does play cricket, but very infrequently.2 → not infrequently 