These she prolonged until she had hobbled to the door, when she exchanged them for a sour malignant look, and twisting her under-jaw from side to side, muttered hearty curses upon the future Mrs Gride, as she crept slowly down the stairs, and paused for breath at nearly every one.
There are no more uses of "malignant" in the book.
Show samples from other sources
Gey and his wife, Margaret, had spent the last three decades working to grow malignant cells outside the body, hoping to use them to find cancer’s cause and cure.
Rebecca Skloot -- The Immortal Life of Henrietta Lacks
He hit it [the shark] without hope but with resolution and complete malignancy.