Oni means affliction, poverty, misery, or distress. It appears about 36 times. It describes the condition of those who suffer — whether from oppression, poverty, or divine discipline.
God sees the affliction of His people. 'I have indeed seen the oni of my people in Egypt' (Exodus 3:7) sparked the Exodus. God is repeatedly described as the defender of the afflicted. The Suffering Servant was 'a man of sorrows, acquainted with grief' — divine solidarity with human affliction.