Here in the southern U.S. the alligators lie dormant during the winter. Frankly, I do not miss them. So do the snakes and I miss them even less.

The literal meaning is 'sleeping', as opposed to active. A virus can lie or be dormant in your body in an inactive state. A dormant volcano is quiet, not ejecting material from within. A law or provision is dormant if it has ceased to be applied or enforced. Something which is (lying) dormant can be activated or reactivated, so it is not dead or, in the case of a volcano, extinct.

inactive or unnoticed

To not be active or it can be thought of as a state of sleep. Plants go dormant in the winter. Bears hibernate (a certain kind of dormancy). When volcanoes are not active, i.e. not erupting, spewing smoke, etc, they are dormant. Even enforcement of a rule/law could be see as a state of dormancy in the enforcement of the law.