Synonyms for Supine (same or very similar meaning)
WordNet sense 1 (lying face upward):
resupineWordNet sense 2 (not upright in position or posture):
unerectWordNet sense 3 (offering no resistance):
resistless, unresistingWordNet sense 4 (lacking in energy or will):
inactive, passiveFrom the ODE community, based on WordNetadd/edit