Definition & Meaning of "deadass"in English

What is the origin of the term "deadass" and how is it used?

Deadass is a slang term that appeared in early 21st-century American English, especially in New York City, to describe a person considered dull, lifeless, or boring. The term comes from combining "dead" (meaning lifeless or lacking energy) with "ass" for emphasis, literally labeling someone as completely lacking vitality or excitement. Historically and today, it is informal and mildly insulting, used in casual speech to critique someone's personality, behavior, or energy rather than in formal contexts.