Real Dictionary

disorder
Disorder is a state of being untidy, badly prepared, or badly organized.
variable noun: A disorder is a problem or illness which affects someone's mind or body.
variable noun: Disorder is violence or rioting in public.

disorder in American English
a lack of order; confusion; jumble
to throw into disorder; disarrange
noun: lack of order or regular arrangement; confusion
transitive verb: to destroy the order or regular arrangement of; disarrange

disorder in British English
to upset the order of; disarrange; muddle
noun: a lack of order; disarray; confusion

disorder in Insurance
noun: A disorder is a mental or physical illness which prevents part of your body from working properly.