also: あくだま
noun
Refers to a person who is evil or plays the villain role, often in contrast to 善玉 (good guy). Common in stories, dramas, and metaphorical use.
この映画では、彼が悪玉を演じている。
In this movie, he plays the villain.
善玉と悪玉がはっきり分かれ
It's a story where the good guys and bad guys are clearly divided.
Compound of 悪 (aku, 'evil') and 玉 (tama, 'ball' or 'jewel'). The 玉 here is a suffix used for roles or types of people, as in 善玉 (good guy) and 借り玉 (debtor). The reading あくたま is more common, with あくだま as a variant.