This is the 594th most frequent German word.
guten
"Guten" is the declined form of "gut," meaning "good."
In this sentence, 'gutes' is the nominative or accusative neuter singular form of 'gut', matching the neuter noun 'Gefühl'.
Er hat ein gutes Gefühl für Musik.
He has a good feeling for music.
Here, 'guten' is the dative feminine singular form of 'gut', corresponding to the feminine noun 'Mahlzeit' in the prepositional phrase after 'nach'.
Nach einer guten Mahlzeit fühle ich mich energiegeladen.
After a good meal, I feel energized.
The word 'guten' is the accusative masculine singular form of 'gut', used here to agree with the noun 'Morgen' in the context of expressing a well-wished greeting.