This second root anah (distinguished from H6030, 'answer') means to press down, afflict, or humble — whether by others' oppression or through self-humbling before God. Fasting is often described as 'afflicting the soul' (anah nephesh), a deliberate act of humility before God.
The suffering servant of Isaiah 53 is 'afflicted' (anah) — pressed down under the weight of others' sin. This connects to the wider OT theme of the 'poor and afflicted' (ani/anav) who are uniquely near to God. Jesus's beatitude 'blessed are the poor in spirit' draws on this tradition. To be anah-ed — whether by suffering or deliberate fasting — creates the posture of dependence that God honors.