This is the 10136th most frequent German word.
perfekter
"Perfekter" means "more perfect" or "perfect" (comparative form of "perfekt").
The word 'perfekter' is used here as an adjective in the masculine nominative singular form, agreeing with the noun 'Tag', which is masculine singular.
Das ist ein perfekter Tag für ein Picknick.
This is a perfect day for a picnic.
The word 'perfekten' appears in its masculine accusative singular form, harmonizing with the noun 'Plan' in this sentence.
Sie hat einen perfekten Plan vorgeschlagen.
She suggested a perfect plan.
The term 'perfekten' is employed in the masculine dative singular form aligning with the noun 'Ort' after the preposition 'an einem'.