Malevolent and maleficent are both adjectives describing wicked people or forces, but they differ slightly. Malevolence involves having ill will or wishing harm on others without necessarily acting on these feelings, while maleficence involves action intending to cause harm.
Examples
For example, notice how the malevolent entities in these sentences are malicious in attitude but not necessarily in action:
The American bass-baritone makes a memorable villain, darkly malevolent in voice and manner, with impeccable German diction and projection. [Chicago Tribune]
Imagine a malevolent version of Ricky Gervais playing King George VI, instead of Colin Firth. [Independent]
He’s also, it should be noted, a super-intelligent vegetable from outer space, a sort of sentient, malevolent carrot with no mercy or emotion. [AV Club]
And in these examples, those who are maleficent act on their evil impulses:
For the media reporting on Iraq it has been a matter of headlining the efforts of maleficent terrorists and burying the news of progress and successes, or not reporting them at all. [American Thinker]
… but to reach it we have to slay the false self, the old man, which is informed by an actively maleficent agency, “flesh” which is hostile to “spirit.” [Christian Mysticism]
The young wife whom Douglas married, and the two children she bore him, also came in for part of her alleged maleficent[Pg 33] enchantments. [Witch Stories]
