رَأَيْتُ رَجُلًا فِي السُّوقِ.
I saw a man in the market.
Here the indefinite noun first signals an unidentified individual. To assert depreciation, grandeur, or alarm, the analyst needs additional contextual evidence. Indefiniteness itself does not prove those effects.
رَأَيْتُ رَجُلًا عَجِيبَ الشَّأْنِ.
I saw a man of extraordinary standing.
The adjective now supplies evidence of exceptional character. A precise analysis assigns each effect to its cause: indefiniteness introduces the referent; descriptive wording qualifies him.