(1) (of flora or fauna) in imminent danger of extinction
"An endangered species"
WiktionaryText
Adjective
in danger, at risk, said of something where there is a strong possibility something bad will happen to it (for example, a species in danger of going extinct)
1825, Sir Walter Scott, The Betrothed
I have but done my devoir, lady, as a good knight, in defence of an endangered maiden...
