Cougar
late 18th century: from French couguar, abbreviation of modern Latin cuguarcarana, from Guarani guaçuarana .
wiktionary
From French couguar, from Portuguese cuguardo, a deformation of Brazilian Portuguese suçuarana (earlier çuçuarana), perhaps from Tupian ( suasuarana(“deerlike animal”), from suasú(“deer”); compare sɨwasuarána(“cervine”)) or perhaps from Guaraní ( guaçuara). [1]
etymonline
cougar (n.)
large cat peculiar to the Americas, 1774, from French couguar, Buffon's adaption (influenced by jaguar) of a word the Portuguese picked up in Brazil as çuçuarana, perhaps from Tupi susuarana, from suasu "deer" + rana "false." Another proposed source is Guarani guaçu ara. Evidently the cedillas dropped off the word before Buffon got it. The cat also goes by the names puma, panther, mountain lion, and catamount.
Slang sense of "older woman (35-plus) who seeks younger males as sex partners" is attested by 2002; said in some sources to have originated in Canada, probably from some reference to predatory feline nature.
