1. Occurring by chance. See synonyms at chance.
2. 1. Occurring at irregular or infrequent intervals; occasional: casual employment at a factory; a casual correspondence with a former teacher.
   2. Unpremeditated; offhand: a casual remark.
3. 1. Being without ceremony or formality; relaxed: a casual evening with friends.
   2. Suited for everyday wear or use; informal.
4. Not serious or thorough; superficial: a casual inspection.
5. 1. Showing little interest or concern; nonchalant: a casual disregard for cold weather.
   2. Lenient; permissive: a casual attitude toward drugs.
6. Not close or intimate; passing: a casual acquaintance with avant-garde music.

1. One that serves or appears at irregular intervals, especially a temporary worker.
2. casuals Casualwear: sent my casuals to the cleaners.
3. A soldier temporarily attached to a unit while awaiting permanent assignment.

[Middle English casuel, from Old French, from Latin cāsuālis, from cāsus, event. See case¹.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.