Is Lying is still a sin?

is lying still a sin? to most people lying is a way of life, but are they cheating punishment... or them selfs. if people go to heaven for every sin then no one would be in heaven, lying isn't even mentioned in the 7 deadly sins gluttony, wrath, greed, pride, lust, sloth, and envy. people are feeble and say they don't lie but really they lie to make them self believe they are more powerful then they really are. they think they can change facts by lying. but really their only changing the outcome in the end. Life is life is like a test and god is our teacher, if you fail you repeat or can't retake and simply are dropped out . failing is the test of a pure soul is a gate way to hell so can something every person has done before at least once a sin. so i ask you this, is lying really a sin?