Synonyms for Cautionary (same or very similar meaning)
WordNet sense 1 (tending to ward off):
preventive, prophylacticWordNet sense 2 (intended or adapted to afford protection of some kind):
protectiveWordNet sense 3 (serving to warn):
admonitory, exemplary, monitory, warningWordNet sense 4 (deterring from action):
dissuasiveFrom the ODE community, based on WordNetadd/edit