"Build a B*tch" is about rejecting the idea that a person's worth or attractiveness can be reduced to physical attributes or cosmetic enhancements. The lyrics express frustration with the notion that someone can be "built" or customized to fit a particular ideal or desire, and assert that true beauty and value come from within. The song also touches on themes of self-acceptance and the importance of being true to oneself, despite societal expectations or pressure to conform. The speaker asserts that they are not a product or object to be manipulated or changed, but rather a complex and imperfect human being with their own unique qualities and flaws. The song celebrates individuality and empowerment, and encourages listeners to embrace and celebrate their own imperfections.