Meaning of IRREGULAR in English
1 not regular in size/shape/frequency
▪ highly , very
▪ rather , slightly , somewhat
The cells are slightly ~ in shape.
2 not allowed according to the rules
▪ be , seem
▪ highly , most , very
It would be highly ~ for a police officer to accept money in this way.
▪ slightly , somewhat
some somewhat ~ business practices
Irregular is used with these nouns: ↑ breathing , ↑ cycle , ↑ heartbeat , ↑ patch , ↑ rhythm , ↑ shape , ↑ verb
Oxford Collocations English Dictionary. Оксфордский английский словарь словосочетаний . 2012