1. A failure to function normally
   "The spacecraft's mission was aborted due to a malfunction in the oxygen system"

1. Fail to function or function improperly
   "the coffee maker malfunctioned";
   - misfunction

Derived forms: malfunctions, malfunctioning, malfunctioned

Type of: break, break down, conk out [informal], die, fail, failure, give out, give up the ghost [informal], give way, go, go bad, pack up [Brit, informal]

Antonym: function

Encyclopedia: Malfunction