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"- John F.Kennedy
controlled by the autonomic nervous system; without conscious control; "involuntary muscles"; "gave an involuntary start"
(used informally especially for emphasis); "a real honest-to-god live cowboy"; "had us a high old time"; "went upriver to look at a sure-enough fish wheel"