occasional

occasional, uncommon, scare, rare

这些形容词均含“稀罕的、很少发生”之意。
occasional: 指偶然、不时或间或发生的事，侧重无规律可循。
uncommon: 指一般不发生或很少发生的事情，故显得独特、异常与例外。
scare: 指暂时不易发现、不存在或数量不足，供不应求的东西。
rare: 指难得发生的事或难遇见的人或事，侧重特殊性。

形容词 occasional:

1. occurring from time to time
2. occurring or appearing at usually irregular intervals
   同义词：episodic
3. occuring from time to time
   同义词：casual

1. He's someone I have an occasional chat and joke with.
   我偶然跟他闲聊，一起说笑话。
2. Her kindness and generosity cancel out her occasional flashes of temper.
   她为人厚道、慷慨大方，倒也弥补了她偶尔发点儿脾气。
3. He is only an occasional workman.
   他只是个临时雇工。
4. I only smoke an occasional cigar.
   我只是偶然抽一支雪茄。

oc.ca.sion.al

adj.Abbr. occas.（形容词）缩写 occas.

Occurring from time to time.See Synonyms at periodic
偶发的：时不时地发生参见 periodic
Not habitual; infrequent:
非经常的：非习惯性的；不经常的：
例句：
took an occasional glass of wine.
偶尔喝瓶酒

Created for a special occasion:
特殊场合的：为特殊场合而制的：
例句：
occasional verse.
应时诗节

Intended for use as the occasion requires:
临时的：因场合需要而使用：
例句：
an occasional chair.
临时的椅子

Acting as a cause.
作为原因的
Acting in a specified capacity from time to time:
不时地在某特定机构服务的：
例句：
an occasional hunter.
临时猎户