Amam (עָמַם) means to become dark, dim, or obscured — to have one's luster fade or glory become hidden. The word appears in Lamentations where it describes the once-glorious gold of Jerusalem now tarnished. It captures the tragedy of diminished glory.
The darkening of what was once brilliant is one of Lamentations' chief griefs. Gold doesn't tarnish under normal conditions — its loss of luster requires extraordinary defilement. Theologically, amam points to the catastrophe of exile as the inverse of glory: where God's presence (shekinah) once radiated in the Temple, now shadow. The prophetic expectation is the restoration of glory: Isaiah 60:1 "Arise, shine, for your light has come!" — the amam reversed. In Christ, the glory hidden (amam) in the incarnation is finally unveiled at the transfiguration.
The image of tarnished gold in Lamentations 4:1 is deliberate: gold is the incorruptible metal, the symbol of divine glory. When it "amam," something unnatural has occurred — sin has reached even to what should be untouchable. The theological weight is enormous: exile has obscured the image of God in his people. Restoration is nothing less than the re-brightening of the gold — the re-glory-ing of humanity.