WordNet sense 1 (lacking stability or fixity or firmness):

unstable

WordNet sense 2 (causing or characterized by jolts and irregular movements):

bumpy, jumpy, jolting, jolty

WordNet sense 3 (abounding in rocks or stones):

stony, bouldered, bouldery

WordNet sense 4 (having or caused by an irregular surface):

rough, unsmooth

WordNet sense 5 (not easy; requiring great physical or mental effort to accomplish or comprehend or endure):

difficult, hard