The motor is locked up and won't turn over.
There are a couple things to look at before the engine is condemned. First, try to turn the engine over by hand. If it does turn, it could be starter related. If not, remove the spark plugs and drive belt(s) and try again. If it does turn now, it is a coolant leak or seized accessory. A qualified mechanic from YourMechanic can come out and diagnose your engine’s turn over issue to determine what repairs are needed to move forward.