The word "unfit" means not suitable or not good enough for a particular purpose or situation. It suggests that something or someone lacks the necessary qualities or abilities needed for that specific purpose. Full definition
Most dogs and cats eat processed pet diets containing byproducts and ingredients deemed unfit for human consumption (healthypets.mercola.com)
Under European law, mussels that contain more than 300 viable E. coli per 100 grams of flesh are deemed unfit for human consumption. (newscientist.com)
Examples of unfit parenting include drug or alcohol abuse, instances of child abuse or neglect, or situations in which the child is subjected to dangerous circumstances. (divorcesource.com)