infrequent
/ɪnˈfriːkwənt/adjective
- not occurring often; rare不经常发生的; 偶有的; 罕见的：
her visits were so infrequent.
她真是很少来访。
派生词
infrequency
nouninfrequently
adverb词源
mid 16th cent. （in the sense 'little used, seldom done, uncommon'）: from Latin infrequent- from in- 'not' + frequent- 'frequent'.