Dictionary:

mala fide

  (mā'lə fī'dē, mä'lä fē'dĕ)

With or in bad faith.

[Latin malā fidē : malā, feminine ablative of malus, bad + fidē, ablative of fidēs, faith.]

adjective

Not being what one purports to be: ambidextrous, disingenuous, insincere, left-handed. See honest/dishonest.

[Latin, Bad faith.]

A mala fide purchaser is one who buys property from another with the knowledge that it has been stolen. In contrast, a bona fide purchaser is one who does so with no knowledge that the seller lacks good title to the property.

With bad faith; treacherously.