preventive

UK: /prɪˈvɛntɪv/ US: /prɪˈvɛntɪv/ ,(pri ven′tiv)

WordReference Random House Learner's Dictionary of American English © 2025

pre•ven•tive /prɪˈvɛntɪv/  also pre•vent•a•tive /prɪˈvɛntətɪv/   adj. 

1. of or relating to prevention:
   preventive measures; preventive medicine.

n. [countable]

2. Medicine a drug or other substance for preventing disease.
3. a person or thing that prevents something.

See -ven-.

WordReference Random House Unabridged Dictionary of American English © 2025

pre•ven•tive  (pri ven′tiv), adj. 

1. Medicine of or noting a drug, vaccine, etc., for preventing disease; prophylactic.
2. serving to prevent or hinder:
   preventive measures.

n. 

3. Medicine a drug or other substance for preventing disease.
4. a preventive agent or measure.

Also, pre•vent•a•tive  (pri ven′tə tiv) (for defs. 2, 4).

• prevent + -ive 1630–40

pre•ven′tive•ly, adv. 
pre•ven′tive•ness, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

preventive / prɪˈvɛntɪv/ adjective

1. tending or intended to prevent or hinder
2. tending to prevent disease; prophylactic
3. (in Britain) of, relating to, or belonging to the customs and excise service or the coastguard

noun

1. something that serves to prevent or hinder
2. any drug or agent that tends to prevent or protect against disease
3. another name for contraceptive

Also (except for sense 3): preventative

preˈventively adverb