not achieving what you want to achieve; not having any effect The new drug was ineffective. ineffective management ineffective in doing something The law proved ineffective in dealing with the problem. opposite effective Word Origin mid 17th cent.: from in- + effective.Extra examples These policies have proved ineffective. These weapons are totally ineffective against tanks. chemicals that are very ineffective in killing weeds High interest rates proved to be ineffective in reducing inflation. It has been criticized as an unfair and ineffective system. She was offered psychotherapy, but this proved ineffective. The evidence demonstrates that punishment is ineffective as a deterrent. The exemption clause in the contract is rendered ineffective by the new law. The government continued with its much-publicized but largely ineffective policy of economic sanctions.