voluntary vs compulsory
- controlled by individual volition
- of your own free will or design; done by choice; not forced or compelled
- composition (often improvised) for a solo instrument (especially solo organ) and not a regular part of a religious service or musical performance
- (military) a person who freely enlists for service
Other ocular signs include involuntary rhythmic movement of the eyeball.
The voluntary muscles are regulated by the parts of the brain known as the cerebral motor cortex and the cerebellum.
At election time the party needs a lot of voluntary helpers.
- required by rule
Retirement is likely to move from an abrupt halt at a fixed age to a more gradual withdrawal, with the abolition of compulsory retirement ages.
Article 13 requires, subject to Article 15, that authorized warehouse keepers shall give compulsory guarantees to cover movement of the dutiable goods.
Medical inspections for schoolchildren become compulsory by law.