WordNet sense 1 (done with very great haste and without due deliberation):

hasty, overhasty, precipitant, precipitate, precipitate

WordNet sense 2 ((of a shore or shoreline) characterized by steep cliffs or precipices):

clifflike, cliffy

WordNet sense 3 (extremely steep):

abrupt, sharp

WordNet sense 4 (having a sharp inclination):

steep