Nerdle = a NON-SEXY female nerd. A SEXY & petite female nerd is a "Nerdette". If she has big tits and a big hips (but NOT big anywhere else) she is a "Nerdess" (ner-DESS, ie, Nerd/goddess).
I'd never go out with Gertrude; she's a nerdle. Now, her sister Vanna, on the other hand, I'd love to go out with her, but, she is a Nerdette, and I just am not smart enough to impress her.
A cross between a nerd and a turtle - Whilst the nerd stays in dark enclosed areas , the turtle represents its slow and delicate walking phase in life.
A nerd walks 2 steps
"OH EM GEE , LIGHT!"
*turtle walks* (2 steps in 8 hours)
If you combine both a nerdle is born.