gray cougar 

An older woman, usually over 55 years, who still acts or thinks like a cougar but is beginning to show her age. While generally attractive, the wrinkles, gray hair, and loss of firmness are getting harder to hide. Another indication is if she surrounds herself with younger cougars. She doesn't have the stamina to perform like a typical cougar, but she may initiate conversation with prey and allow other cougars to steal the prize. As with all cougars, she will be very confident, possibly flirtateous if the prey is significantly younger. Gray cougars tend to be a bit more reserved in public settings, but may surprise you once in private.

College guy to his wingman: Hey, we gotta get outta here, this place is full of gray cougar and they're starting to notice us.

gray cougar by firescout September 5, 2013

Grancougar

A single, divorced or widowed woman, with grandchildren, that is 50 years of age or older that has an eye for much younger men.

Those grancougars that Matt is supervisor for will really miss him if he changes jobs.

Grancougar by Sir Toppem Hat April 8, 2009