No more premiums are paid into a plan but the payments already received, continue to be invested until the plan reaches maturity.
It is possible, with certain policies having an investment content e.g. endowment, to cease paying premiums and retain a paid-up policy which will pay out on eventual claim. Also another name for ‘preserved' pensions.
A policy/benefit is said to be paid up if the premium has been suspended whereas the benefit is still valid.