Wiktionary
nonregular
a. (context mathematics English) Not regular. n. One who is not a regular.
Usage examples of "nonregular".
The different domains are a necessary consequence of the first moments of creation—and you'll notice that the domains would be nonregular in shape, and that fits in well with the observed fibrous structure of the universe.
His appointment list had been thoroughly checked - the Social Security numbers of all nonregulars are run through the FBI's crime computers - and the visitors themselves would, of course, be subjected to the most thorough searches that can be made without an actual pat-down.