preventative
pre-ven-ta-tive
noun
A substance or action used to stop something bad from happening or spreading.
"She took a preventative against motion sickness."
adjective
Intended to stop something harmful or undesirable from occurring or developing.
"They implemented preventative measures to avoid accidents."
Thesaurus
Synonyms: pre-emptive, obstructive, preemptive, hindering, preventive, frustrative, clogging, prohibitory, impeding, preclusive, deterrent, blockading
Antonyms: permissive