寝食い (negui: living in idleness) to sleep + to eat
Note the less common yomi for 食. The verb 食う (kuu) still means “to eat” and “to have a meal,” as well as “to hold onto (in one’s mouth)” or “not to let go.”
A native speaker tells me, “It has become an unsophisticated kind of word to use. It is mostly applied to animals, but we still use 食う a lot on informal occasions, including referring to humans eating. Close friends use it among themselves. Also, men use it but women usually don’t.”