Relating to or based on individual choice, judgment, or authority; optional rather than required or automatic.
From 'discretion' (the power to make decisions) plus the suffix '-al' (relating to). 'Discretion' comes from Latin 'discretio' (separation, discernment).
In law and government, 'discretional' power is what makes judges able to make different sentences for similar crimes—it's the freedom to choose, which is powerful but also sometimes controversial because it can lead to unfair bias.
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