1. spend a lot of money
splash out on clothes/a holiday/a new car
To splash out means to spend a large amount of money without worry or inhibition. Similar in meaning to 'splurge' and 'go the whole hog' or 'push the boat out'. If you 'splash out' on something you decide to spend a lot of money on it. "We have both been working hard this year and think we should splash out on a holiday." This is an informal phrase used more often in social contexts.