noun
Refers to food left uneaten after a meal. Often used in contexts of not wasting food or cleaning one's plate.
See also: 食べ残し
食い残しを冷蔵庫に入れておいた。
I put the leftovers in the fridge.
彼は食い残しを犬にやった。
He gave the leftovers to the dog.
Synonymous; 食べ残し is slightly more common and neutral, while 食い残し can sound a bit more informal or masculine.
Compound of 食い (stem of 食う 'to eat') + 残し (stem of 残す 'to leave behind').