Lethargic Cat Not Eating. Lethargy is an indication of your cat not feeling well and could relate to a relatively minor medical condition or could be a sign of a more serious illness. These signs could be just dietary related or compatible with a gastrointestinal inflammation/infection.

I think my cat is lethargic but eating. Just like us, cats can occasionally feel lethargic but if they are acting like this for an extended period of time and they are also refusing to eat or drink then this calls for an emergency visit to the vet. For example, if your cat is lethargic and not eating, acting overly affectionate or aggressive, or is losing or gaining weight, they are probably ill.