New International Version
An honest witness tells the truth, but a false witness tells lies.

American Standard Version
He that uttereth truth showeth forth righteousness; But a false witness, deceit.

Berean Study Bible
He who speaks the truth declares what is right, but a false witness speaks deceit.

Douay-Rheims Bible
He that speaketh that which he knoweth, sheweth forth justice: but he that lieth, is a deceitful witness.

English Revised Version
He that uttereth truth sheweth forth righteousness, but a false witness deceit.

King James Bible
He that speaketh truth sheweth forth righteousness: but a false witness deceit.

World English Bible
He who is truthful testifies honestly, but a false witness lies.

Young's Literal Translation
Whoso uttereth faithfulness declareth righteousness, And a false witness -- deceit.

Proverbs 12:17 Additional Translations ...