UVM_HIGH = 300, UVM_FULL = 400, UVM_DEBUG = 500 } uvm_verbosity; i.e., if you run with +UVM_VERBOSITY=UVM_NONE, then only UVM_NONE messages shall be printed. If you run with +UVM_VERBOSITY=UVM_LOW, then only the UVM_NONE, UVM_LOW messages shall be printed and so...