infrequently

Word family  noun frequency ≠ infrequency adjective frequent ≠ infrequent verb frequent adverb frequently ≠ infrequently

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++in·fre·quent·ly /ɪnˈfriːkwəntli/ adverb  1  not often 不经常发生地，罕见地 SYN rarely OPP frequently Jeremy does play cricket, but very infrequently. 杰里米确实玩板球，但次数很少。2  not infrequently formal fairly often 经常地 The censors changed some names and dialogue and, not infrequently, banned controversial films. 审查官对电影里的一些名字和对话进行修改，并常常禁止有争议的电影发行。

in·fre·quent·ly adverbChineseSyllable  

infrequently
in‧fre‧quent‧ly /ɪnˈfriːkwəntli/ adverb1. not often
   SYN  rarely
   OPP  frequently:
    Jeremy does play cricket, but very infrequently.
2. not infrequently formal fairly often:
    The censors changed some names and dialogue and, not infrequently, banned controversial films.