a. Lacking qualities necessary for effective conduct or action: an incompetent manager.

b. Inadequate for or unsuited to a particular purpose or application: "Because so many diseases fluctuate randomly over time, patients sometimes spontaneously improve despite incompetent treatment" (Richard A. Friedman).

c. Not functioning properly in the body: an incompetent heart valve.

a. Not legally qualified, as testimony that does not meet the standards for admissibility or a juror whose personal interest in the outcome of the case does not allow him or her to serve.

b. Lacking sufficient mental ability or awareness: a defendant incompetent to stand trial.