infrequent

形容词 infrequent:

1. not frequent; not occurring regularly or at short intervals

1. Place for permanent or long-term storage of data, from which retrieval is infrequent. A computer archive, for instance, may be on magnetic tape.
   用于永久或长期存储不常检索的数据的地点(介质)。例如，计算机的档案文件可放在磁带上。
2. Difficult, incomplete, or infrequent evacuation of dry, hardened feces from the bowels.
   便秘有困难的、不完全的或不经常从肠道排泄干燥且硬的大便
3. Explosions, though infrequent, are an occupational hazard for coal-miners.
   矿井爆炸虽然不常发生，但却是煤矿工人职业中的危险。

in.fre.quent

adj.（形容词）
Not occurring regularly; occasional or rare:
不经常的：不经常发生的；偶然的或罕见的：
例句：
an infrequent guest.
一位稀客

Situated or placed at rather wide intervals, as in time or space:
罕见的：位于或置于大间隔的，如时间或空间上的：
例句：
infrequent oases in the desert.
沙漠中鲜有的绿洲

【引伸】
infre.quence 或
infre.quency
n.（名词）
infre.quently
adv.（副词）