It means you haven't paid your rent, your lease has a clause in it that says that your landlord can declare your rights, and the lease, forfeited by your breach, and without having to go to court, and your landlord is going to have the locks changed so they can rent the place out to a new tenant.
As you lease presumably states, you're still liable for landlord's damages, including unpaid rent not paid by a another tenant, forfieture costs, damages to the premises, advertising costs, etc. Review your lease, or hire a real estate litigator for help.
I'm only licensed in CA. Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
The term lease "forfeiture" is often used to refer to situations that arise with commercial leases. The landlord of a commercial property has the right to end a lease if a tenant fails to adhere to the terms of the contract.
Typically, landlords exercise the right to a lease forfeiture when a tenant has failed to pay the agreed amount of rent on a commercial property. In some cases, however, a landlord will also exercise its forfeiture rights because the tenant has breached the lease agreement in some other manner, e.g., the tenant is engaged in illegal activity on the premises.
Under California law, a lease terminates on the day that the landlord files its unlawful detainer action following a properly given 3-day notice to pay rent or quit, together with an election by the landlord declaring the lease forfeited, coupled with the tenant's failure to timely cure the default.
However, California law provides that even though a lease has been terminated, a court may relieve a tenant from the forfeiture of termination in cases of hardship. (California Code of Civil Procedure section 1179).
If you as the commercial tenant get evicted as a result of the unlawful detainer action, the judgment will make you liable for all unpaid rent up to and including the date of the judgment. However, if the court grants the landlord's request for forfeiture of the lease, you will not be liable to pay the rent for the remaining 9 months.