形容詞 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.
   用于永久或長期存儲不常檢索的數(shù)據(jù)的地點(介質)。例如，計算機的檔案文件可放在磁帶上。
2. Difficult, incomplete, or infrequent evacuation of dry, hardened feces from the bowels.
   便秘有困難的、不完全的或不經(jīng)常從腸道排泄干燥且硬的大便
3. Explosions, though infrequent, are an occupational hazard for coal-miners.
   礦井爆炸雖然不常發(fā)生，但卻是煤礦工人職業(yè)中的危險。

in.fre.quent

adj.（形容詞）
Not occurring regularly; occasional or rare:
不經(jīng)常的：不經(jīng)常發(fā)生的；偶然的或罕見的：
例句：
an infrequent guest.
一位稀客

Situated or placed at rather wide intervals, as in time or space:
罕見的：位于或置于大間隔的，如時間或空間上的：
例句：
infrequent oases in the desert.
沙漠中鮮有的綠洲

【引伸】
infre.quence 或
infre.quency
n.（名詞）
infre.quently
adv.（副詞）