Involuntary \In*vol"un*ta*ry\, a. [L. involuntarius. See In- not, and Voluntary.]

1. Not having will or the power of choice.

2. Not under the influence or control of the will; not voluntary; as, the involuntary movements of the body; involuntary muscle fibers.

3. Not proceeding from choice; done unwillingly; reluctant; compulsory; as, involuntary submission.

Source: Webster's Revised Unabridged Dictionary (1913)