/
ˈkaʒjʊəl, 
-zj-/
adj.
    - relaxed and unconcerned. 
▸made, done, or acting without much care or thought:
 a casual remark.
 - not regular or firmly established. 
▸(of a worker) employed on a temporary or irregular basis.
 ▸(of a sexual relationship or encounter) occurring between people who are not established sexual partners.
 - happening by chance; accidental:
 a casual meeting.
 - without formality of style, manner, or procedure.
 
n.
   - Brit. a casual worker.
 - 
(casuals)
 clothes or shoes suitable for everyday wear rather than formal occasions.
 - Brit. a youth belonging to a subculture characterized by the wearing of expensive casual clothing.
 
Derivative
- casually adv.
  - casualness n.
 
Etymology
ME: from OFr. casuel and L. casualis, from casus ‘fall’.