Guaranteed
A guaranteed online poker tournament is a type of tournament in which the final prize pool is guaranteed by the poker room. If the number of participating players in the tournament should not be sufficient to reach the promised prize pool, the poker room will cover the difference.
If, on the other hand, the number of participants exceeds the minimum requirements, then the prize pool will be increased accordingly on top of the guaranteed amount.
For example a guaranteed €1,000 tournament will always have a minimum prize pool of €1,000. So €1,000 guaranteed simply means that a minimum of €1,000 is available to split between the winners even if the number of participants should not be sufficient to meet the €1,000 target.