economical with the truth

Etymology
Believed to be from a quotation by the British-Irish statesman and philosopher (1729–1797): “Falsehood and delusion are allowed in no case whatever: But, as in the exercise of all the virtues, there is an œconomy of truth. It is a sort of temperance, by which a man speaks truth with measure that he may speak it the longer.”

Adjective

 * 1)  Not telling the whole truth, especially in order to present a false image of a situation; untruthful; lying.