Unfiltered olive oil (olio non filtrato) retains small olive particles and water, giving it a cloudy appearance and more intense flavor. It is especially popular right after harvest.
Filtered olive oil is clear and more stable, as water and sediment have been removed. This means a longer shelf life and lower risk of oxidation.
Both have their place — unfiltered oil is excellent enjoyed fresh on bread, while filtered oil is better for long-term storage and everyday use.