The origin of the phrase “fair play” is largely credited to Shakespeare who coined the phrase and used it in several of his plays. Today the phrase is often associated with sportsmanship especially in many leading games like football and cricket so much so that some countries have incorporated it into their legislation.
In sports parlance fair play means properly conducted conditions for a game, giving all participants an equal chance. When used in contexts other than games it means fairness and justice.
Therefore one can say that fiscal fair play refers to properly designed systems where every taxable person pays according to their ability and the tax revenue is applied judiciously for the benefit of all.