involuntary
adj.something that happens without you choosing to do it. You use this to describe a movement or action your body makes on its own.
adj.done without conscious control or intention; occurring as a reflex or automatic response. Often used in medical or physiological contexts to describe muscle movements.
“A sneeze is an involuntary reaction to dust.”
“The patient experienced involuntary muscle spasms in his left leg after the long surgery.”
“While some physical responses are purely involuntary, others can be partially regulated through deep breathing and focused mindfulness techniques.”
Often appears before nouns like 'action', 'response', 'muscle', or 'movement'.
Involuntary is an adjective and must modify a noun; it cannot be used as a noun itself.
“This led Pfungst to conclude that Hans was simply responding to involuntary signals from his owner, signals that his owner did not even realize he was providing.”
From in- + voluntary, from Late Latin involontarius, from in + volontarius.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.