1.
yaksha, demon, fierce spirit
A class of supernatural being from Indian mythology, adopted into Buddhism. In Japanese, 夜叉 typically refers to a fierce, terrifying demonic being, though in the original Indian tradition yaksha could be either benevolent or malevolent.
2.
fierce person, demon-like person
Used figuratively to describe someone who is terrifyingly fierce, ruthless, or relentless.
She's usually gentle, but when it comes to work she transforms into a demon.
Usage
Most commonly used in similes: 夜叉のように (like a demon), 夜叉のような形相 (a demonic expression). The word conveys a sense of terrifying ferocity.
Common collocations
Cultural note
From Sanskrit "yakṣa." In Japanese Buddhism and folklore, 夜叉 is one of the 八部衆 (eight classes of supernatural protectors of Buddhism). The word appears in literary works such as 泉鏡花's novel 高野聖.