Pantsload means any of the following:
A) A
euphemism for
shitload.
Gee, mom, that's a pantsload of ducks over there!
B) A load of
something sufficient to fill a pair of
trousers.
After having sex on the beach, Andrea and her partner Rick both found themselves with pantsloads of sand.
C) Loosely, an
unreasonably large amount of something.
20 terabytes? That's a pantsload of disk space!