Translation:This is the appropriate hat.
Could I not say "This is the proper hat"?
Would you really say sombrero adecuado if it was the "right hat?" Wouldn't you say sombrero correcto? Adecuado means suitable or adequate... which means it works, but it's not necessarily THE right hat... right? Or am I somewhat off here?
Lo acepta: This is the suitable hat.
adecuado is used as the right one (too)
Why not "This hat is adequate?"
That would be "Este sombrero es adecuado." There's a slight difference; one is talking about the fact that this is THE adequate hat, and the other is saying this hat just happens to be adequate.
How about "Este es el sombrero mejor" ?
IE "This is the best hat" I can not see "right" as a synonym for "adequate" which at least in English means "sufficient"
whereas "right" usually means optimized