Endangered species is a species facing a high risk of extinction in the wild in the near future due to a decrease in its habitat, excessive predation or poaching.
Vulnerable species are those for which presently the population is sufficient but is undergoing depletion due to some factors so that it is facing the risk of extinction in a medium term.
Rare species are species with naturally small populations, either localized or thinly scattered.
Extinct species are the taxon completely eliminated or died out from Earth, e.g., Dodo.