"improper means" is correct and usable in written English.
You can use it to refer to methods or activities that are not morally or legally acceptable. An example sentence using the phrase would be: "He was accused of obtaining the money through improper means."
Most people get at least some groceries or household goods through "acquaintances," or other improper means.
Edward Levi did not believe that the end ever justified improper means, least of all in the law.
Usually he has no substantial chance of showing that the one or more interrogators used improper means to elicit involuntary statements from him.
Once a person obtains a Social Security number, through proper or improper means, he said, the government has little control over its use.
Sulaiman, who according to published reports yesterday is going to resign next week, denies that King or any other promoter has ever used improper means to influence him.
Between 2003 and 2009, the court said, the four defendants used "improper means" to gain information that allowed Rio Tinto to "jack up the price that China paid" for its iron ore imports.
Corruption is not a word to be used lightly, so let's be disciplined by the Merriam-Webster dictionary's definitions: "dishonest or illegal behavior especially by powerful people" and "inducement to wrong by improper or unlawful means". We can stipulate that the tax bill is not illegal.
Evidence is generally admissible in criminal proceedings in Jamaica even if obtained by improper or unfair means, making arguments not to arrest Coke unsustainable.
There is now a deep ideological relationship ... ....Sorry to be a party-pooper, but this relationship, while by no means improper, may be no deeper than others recently formed at the White House.
The company says its drugs could only have been attained "through improper or illegal means" because of the restrictions they put into place regarding their products, and it asked for the courts to bar Nebraska from using its drugs and to order the state to return them.
Federal, state, and local government have a long history of using improper and illegal means to thwart social change -- from having Federal troops break strikes in the 1800's to the Federal Bureau of Investigation's Cointelpro operation in the 1960's and 70's.
