a person who is at the lake or talks about the lake excessively, drinks heavily, has prodominate tan lines, a large collection of mardi gras beads, and a talent for getting girls naked. (can be male or female)
Lysa is such a lake rat. She's always topless with other girls, wasted, and has the most beads I've ever seen.
by G'na September 8, 2006
A promiscuous girl that will flirt/fuck/blow any guy who has access to a boat hence leading to an invite on that same boat, she will do whatever it takes to get to the lake.
Danielle came to the lake with Eric R. and ended up leaving with a firefighter and a CEO and a dairy man because their boat was better, what a Lake Rat!. I love Don Pedro
by The One and Only CEO/TJ911 June 9, 2009