晴れ着を着て 1. dressed like Christmas beef 2. en fete 3. in Sunday attire 4. in gala 5. in holiday array 6. in one's Sunday best 7. in one's best 8. in one's best bib 9. in one's best bib and tucker
例文
That's najmuddin , the one with the white coat . 白い上着を着ているのがナジムディンです
I am still wearing the white brocade doublet caroline gave me . 僕は今だにキャロラインがくれた白い錦織の上着を着ている