live horse; living horse
Refers to a horse that is alive, as opposed to a dead or toy horse. Often used in the proverb 生き馬の目を抜く.
He finished the work with lightning speed, as quick as plucking out a live horse's eye.
A live horse is depicted in this painting.
Compound of 生き (iki, 'living') + 馬 (uma, 'horse'). The exact historical derivation is straightforward.