I. “+ intransitive verb
Etymology: mal- (I) + function, v.
: to function badly or imperfectly : fail to operate in the normal or usual manner
designed a rifle that would not malfunction
the parachute malfunctioned, opening too late
attributable to some malfunctioning of the nervous system — Edward Sapir
II. noun
1. : the action or fact of malfunctioning
altitudes where malfunction of the plane becomes evident
2. : an instance of malfunctioning
three malfunctions had been reported and rectified before the rocket was finally launched