a young or inexperienced surfer, especially one whose behavior is objectionable
"Every beach has a clown who thinks he knows it all.
Hang-ten outta Santa Fe when surf comes out tomorrow lets go!
And he's always practicing his cowabunga call.
But the menace scrambles when the big waves start to roll.
'Cuse there's nothing worse then a gremmie out of control." - Pearl Jam Song
A large ball of flem or mucus. generally something disgusting and rank.
damn, i just coughed up a gremmie
girl who resembles a gremlin!
what the hell its a gremmie