Question

what does clamber not you up to casementa mean

Answer 1

your ans:-

clamber not you up to casements means that not to climb up to see from the windows

these words are remarked by Shylock to Jessica when he gets to know about the masquerade

Answer 2

to climb up, across, or into somewhere with difficulty, using the hands and the feet:
They clambered over/up the rocks.
I clambered into/onto the bus.
She clambered into bed.