cast away
1. To discard, dispose of, reject, or renounce something or someone. After the divorce, I cast away all mementos from my marriage that were still in the house. The new dictator immediately cast away everyone in the government, replacing them with his personal supporters. I cast away my faith in religion after my wife died.
2. To waste, misuse, or be frivolous with, as of money or resources. The CEO cast away the company's earnings on his own lavish lifestyle. The new director wanted to make an entirely different film, so all that time and work we put into the project have been cast away.
3. Of a ship or sailors, to shipwreck or maroon e.g. on a deserted island. The small fishing vessel, largely destroyed by the storm, was cast away on a tiny piece of land in the middle of the Pacific. The pirates cast away the crew in the lifeboats and made off with their ship and its contents.
cast away
1. Also, cast aside. Discard, reject, as in He picked a book, then cast it aside, or She cast away all thoughts of returning home. [Early 1400s]
2. Squander, waste, as in She cast away a fortune on jewelry. Shakespeare used this idiom in King John (2:1): "France, hast thou yet more blood to cast away?" [Early 1500s]