mal- Also male-.
Improperly; badly; wrongly.
[French mal, from Latin male, badly.]
Some words acquired via French include malady (Latin habitus, having as a condition); maladroit (French à droit, properly); maltreat (French maltraiter); and malcontent (French content, pleased).
Many terms have been formed on English stems, of which a few examples are malnourished, affected by a bad or insufficient diet; maladjusted, failing or unable to cope with the demands of a normal social environment; malfunction, a failure to function normally or satisfactorily; malpractice, improper, illegal, or negligent professional activity or treatment; malodorous, smelling very unpleasant.
Some early examples were spelled male-, though this is long defunct as an active ending: malediction (Latin dicere, to speak); malefactor (Latin facere, do); malevolent (Latin volent-, wishing).