One who spends entirely too much time partaking in muscle building, strength training, cardiovascular, or aerobic activity. Specifically, one who does so at a health club or gym.
Often used derrogatorily by people who do not partake in or understand this lifestyle, some self-proclaimed gym rats use the term as a status symbol or for positive reinforcement.
Rare: The term is sometimes used with homosexual or dim-witted connotations, but both are entirely unfounded (the author of this definition is a gym rat, and does not fit these connotations).
I prefer to work out at home... I don't need to hang around a bunch of gym rats.
Look at those gym rats! They can name all their muscles, but I bet they couldn't tell you what an adjective is!
In terms of sports, if someone is called a Gym rat it is to be taken positively. Someone who puts in the work more than anyone else to become a better player, is considered a gym rat.
Sports commentator 1: Did you see that jump shot, fundamental skills.
Sports commentator 2: Yeah, hes a gym rat and puts in the work.
Some one who goes to the gym everyday
Some one who continually post statuses on their facebook that they are at the gym
Facebook status "Yeah pumping iron at the gym"
Facebook reply comment "You're such a gym rat"
E.G 2:"Claudia is at the gym everyday she's turning into a gym rat"
E.G 3"I don't care if you go to the gym everyday I go 2 days a week like you're suppose to not everyday like you you gym rat"
Someone who spends all their time in a gym but does absolutely zero excercise.
Gym Rat: God I'm so pumped for the gym, time to get fucking juiced!
Does one rep
Gym Rat: FUCK YEAH!!! TIME TO WALK AROUND AND ACT LIKE A BOSS