The question "What is no deposit bonus?" usually comes up after a bonus has vanished, taking its winnings with it. The cause is almost always a condition in the terms: a deadline that passed, a withdrawal made too early, a cap on winnings or a clause about irregular play. Each of these can be seen in advance, and a short read of the terms shows which of them apply to any particular offer.
Every bonus has a deadline, and usually two: one for claiming it and one for completing its wagering requirement. When the second passes, the bonus and any winnings still tied to it are removed, however close the requirement was to completion. Deadlines range from a day for free spin winnings to several weeks for a large match. The clock often starts at the deposit, which means a slow first session already uses part of the available time.
Casinos can change their bonus terms, and most promise that a bonus already claimed stays under the version accepted at the time. The promise matters only if the version can be shown, so saving the terms on the day an offer is taken is worth the minute it costs. The same goes for anything support agrees in chat: a saved copy of the conversation settles more disputes than a memory of it.
Requesting a withdrawal while a bonus is active often cancels the bonus and everything won with it, and some casinos apply the rule even to cash deposited alongside it. A player can usually cancel a bonus on purpose from the account page, which frees the cash balance at the cost of the bonus. Knowing where that option sits, and what it removes, turns an accidental forfeit into a choice made knowingly.
Usually not. Opening more than one account per person or household is a common abuse clause, and it can void the bonus and its winnings.
Often yes. Asking to withdraw while a bonus is active can remove the bonus and its winnings, and some casinos apply this to the deposited cash too.
The bonus and any winnings still tied to it are removed, however close the requirement was to completion, and the clock often starts at the deposit.
Typical examples include betting both sides of an even money bet, switching to low risk play to clear wagering, or sharply raising stakes after conversion.
A limit on how much can be withdrawn from bonus winnings, often a multiple of the bonus or a fixed amount; anything above it is taken back at conversion.