By fair means or foul
Definition 1 of 1
Pro Tip 1/3Moral Ambiguity
The phrase suggests willingness to use unethical methods to achieve a goal, pointing to a moral grey area. 
In his pursuit of wealth, he would acquire it by fair means or foul.
Pro Tip 2/3Strong Determination
Indicates an intense desire to achieve success, no matter what obstacles or rules may be in the way. 
She aimed to top the class by fair means or foul.
Pro Tip 3/3Controversial Actions
Using the phrase can imply that controversial or dubious actions are being considered or have been taken. 
He captured the throne by fair means or foul, causing unrest in the kingdom.