Nouns

(n)preventive, preventative, prophylacticremedy that prevents or slows the course of an illness or disease“the doctor recommended several preventatives”
(n)hindrance, hinderance, hitch, preventive, preventative, encumbrance, incumbrance, interferenceany obstruction that impedes or is burdensome

Adjectives

(s)preventive, preventative, prophylacticpreventing or contributing to the prevention of disease“preventive medicine”, “vaccines are prophylactic”, “a prophylactic drug”
(a)preventive, preventativetending to prevent or hinder