They impede progress

Usage examples of thwarters.

There was a cook shop next to the platform and he ate his breakfast amid a bustle of young Thwarters going to work in the village food fields in a valley lower down.

He paid for his meal with a handful of local coins, then herded his sample cases out of the shop, ignoring the laughter that followed him as the Thwarters noted for the first time the hippity-hoppity progress of the cases on their dozens of short skinny legs and stubby feet.

By noon he'd finished two-thirds of the circuit, had tagged a dozen Thwarters and was near perishing of hunger.