1 not having a shape or pattern that we recognize or can predict 不规则的；无规律的: an irregular shape 不规则的形状

2 happening at times that you cannot predict 不定期的: His visits became more and more irregular. 他的探视越来越不定期了。

3 not allowed according to the rules or social customs 不合规矩的；不合常规的: It is highly irregular for a doctor to give information about patients without their permission. 医生未经病人同意把他们的资料公开是不合规矩的。

4 (grammar语法) not following the usual rules of grammar 不规则变化的: irregular verbs 不规则动词‘Caught’ is an irregular past tense form. caught是不规则变化的过去时形式。 [OPP] for senses 1, 2 and 4regular 第1、2及4义的反义词皆为regular