From Longman Dictionary of Contemporary Englishpantherpan‧ther /ˈpænθə $ -ər/ noun [countable] 1 
HBAa large wild animal that is black and a member of the cat family2 American EnglishHBA a cougar
HBAa large wild animal that is black and a member of the cat family2 American EnglishHBA a cougarExamples from the Corpus
panther• He was cat-cautious, lithe as a panther, and thoroughly at home.• He would move, she guessed, with the supple grace of a panther.• Neither had I, but Siegfried prowled up and down like a caged panther as though willing something to happen.• Rangers coaxed the two remaining panthers down into the Everglades last year.• He solved the Chelsi problem by having her noisily eaten by a Stygian panther in the lab menagerie.• Some of these Knights adopted the panther as their emblem, and the Knight Panther was created.• The idea had reminded the old man of those last two panthers in electronic collars.Origin panther (1200-1300) Old French pantere, from Greek panther 