- 1producing the result that is wanted or intended; producing a successful result Long prison sentences can be a very effective deterrent for offenders. Aspirin is a simple but highly effective treatment. drugs that are effective against cancer Some people believe that violence is an effective way of protesting. I admire the effective use of color in her paintings. opposite ineffective see also cost-effective
- 2[only before noun] in reality, although not officially intended the effective, if not the actual, leader of the party In spite of what they are told, parents have no effective choice of schools. He has now taken effective control of the country.
- 3 (formal) (of laws and rules) coming into use The new speed limit on this road is effective June 1.
adjectivejump to other results
to check the effectiveness of the security system
effectiveness (effectivity nounjump to other results