The Aramaic verb yetav is the equivalent of the Hebrew yatav (H3190), meaning 'to be good, to be pleasing, to go well.' It appears in the Aramaic portions of the Old Testament, particularly in Daniel and Ezra. The concept of something being truly 'good' — pleasing to God and well-ordered — runs through all of Scripture from Genesis 1 ('it was good') to Revelation.
Though an Aramaic verb appearing mainly in the exilic portions of Scripture, yetav reflects the same theological foundation as Hebrew tov: that genuine goodness is defined by conformity to God's will and character. The exile context is significant — even in Babylon, what is truly yetav (good/pleasing) is determined not by the king's decree but by God's standard. Daniel's three friends embody this: what was 'good' in Nebuchadnezzar's eyes was not necessarily good before God.