What is "economical with the truth"

a. (context idiomatic euphemistic English) not telling the whole truth, especially in order to present a false image of a situation; untruthful; lying. Often used with sarcasm or satire

To be economical with the truth literally means to avoid revealing too much of the truth. While the idea may have an approbatory sense of prudence or diplomacy, the phrase is often either used euphemistically to denote dissimulation ( misleading by withholding pertinent information) or else used ironically to mean outright lying.