Sentence:  The <WSD>bluebuck</WSD>, or blue antelope, was the first large African mammal to become extinct in historical times. <WSD>Bluebuck</WSD> numbers began dropping about 2000 years ago and the species was already rare by the 1700s....The last <WSD>bluebuck</WSD> was reportedly killed in 1799. 
Meaning of the word marked with <WSD> tags:  An extinct mammal, (noshow=1), the first large African mammal to become extinct in historical times ("circa" 1800).