1. rise => ris- => rit- "rise, stir up, set in motion, excite".
2. ir- (in- "into, in, on, upon") + rit- "rise, stir up, set in motion, excite" + -ant.
3. => stimulate to action, provoke, incite. (其构词原理与 incite 差不多，incite => 字面含义：make motion(激发、刺激而使其活动)。)
4. => annoy, make impatient.
5. 该的第二层含义：ir- "not" + rit- (from ratus "fixed by calculation; determined; approved; certain, sure; valid" (past participle adjective from reri "reckon, think;" see rate, reason)) + -ant.

irritant 刺激物

来自irritate,刺激，使烦恼。

1. He said the issue was not a major irritant.

他说那个问题不是什么大问题。

2. It may be that the itching is caused by contact with irritant material.

瘙痒可能是由于接触了刺激性的物质而引起的。

3. The noise of traffic is a constant irritant to city dwellers.

车辆的噪音对城市居民是永无止境的骚扰.

4. Irritant. May be a reproductive hazard. Typical PEL 100 ppm.

刺激性. 可能是一个生殖危害. 典型贝利百万分之一百.

5. The cross - subsidy from paying patients is a major political irritant.

这种从付费病人给不能付费病人的跨越补助是今天的主要政治激点.