Origin: Latin suffix -ary
Unvoluntary has 2 different meanings across 1 category:
not subject to the control of the will
"involuntary manslaughter"
"involuntary servitude"
"an involuntary shudder"
"It (becoming a hero) was involuntary. They sank my boat"
Involuntary.
This word combines the prefix un- with voluntary to mean not done by choice. It is formed directly from these two existing English elements.