Synonyms for Malevolent (same or very similar meaning)
WordNet sense 1 (having the nature of or resulting from malice):
maliciousWordNet sense 2 (having or exerting a malignant influence):
evil, malefic, malignWordNet sense 3 (harmful or evil in intent or effect):
maleficent, maleficentFrom the ODE community, based on WordNetadd/edit