We have put together a list of words that are similar to IRREGULAR.

14 Alternative Words Similar to irregular

1 Maverick Adjective      Synonym Words Like Maverick
2 Unorthodox Adjective      Synonym Words Like Unorthodox
3 Regular Adjective      Antonym Words Like Regular
4 Rough Adjective      Related Words Like Rough
5 Casual Adjective      Similar Words Like Casual
6 Improper Adjective      Similar Words Like Improper
7 Occasional Adjective      Similar Words Like Occasional
8 Unconventional Adjective      Similar Words Like Unconventional
9 Unlawful Adjective      Similar Words Like Unlawful
10 Second Noun      Synonym Words Like Second
11 Merchandise Noun      Synonym Words Like Merchandise
12 Product Noun      Synonym Words Like Product
13 Ware Noun      Synonym Words Like Ware
14 Maquis Noun      Hyponym

7 examples of irregular

1 an irregular line; an irregular figure; an irregular verse; an irregular physician; an irregular proceeding; irregular motion; irregular conduct, etc. Cf. Regular.
2 maverick politicians
3 irregular warfare
4 employed on a temporary basis
5 highly irregular behavior
6 atypical clinical findings
7 atypical pneumonia

10 definitions of irregular

1 Not regular; not conforming to a law, method, or usage recognized as the general rule; not according to common form; not conformable to nature, to the rules of moral rectitude, or to established principles; not normal; unnatural; immethodical; unsymmetrical; erratic; no straight; not uniform
2 One who is not regular; especially, a soldier not in regular service.
3 independent in behavior or thought
4 (used of the military) not belonging to or engaged in by regular army forces
5 lacking continuity or regularity
6 falling below the manufacturer's standard
7 (of solids) not having clear dimensions that can be measured; volume must be determined with the principle of liquid displacement
8 (of a surface or shape); not level or flat or symmetrical
9 a member of an irregular armed force that fights a stronger force by sabotage and harassment
10 deviating from normal expectations; somewhat odd, strange, or abnormal
We get our data from many different dictionaries across the web:
Wordnik, Wiktionary, Century, American Heritage, Gcide