A.T. Robertson Commentary Mark 15:37

"And Jesus uttered a loud voice, and gave up the ghost." — Mark 15:37 (ASV)

Gave up the ghost (εξεπνευσεν). Literally, breathed out. See "yielded up his spirit" in Mt 27:50 for discussion for details. Mark uses this word εξεπνευσεν again in verse 39.