irregular /iˈreɡjulə/ adj. 不规则的：an irregular airliner 不定期航班；an irregular verb不规则动词He visits us at irregular intervals.他不定期地来探访我们。

 irregularity /iˌreɡjuˈlæriti/ n. ［u］不规则，无规律：the irregularity of verbs 动词的不规则变化；irregularities of the heartbeat心律不齐