Sunday best 一張羅

Sunday best は一張羅（いっちょうら）の晴れ着、一番上等の服という意味です。5:05 the girls were dressed in their Sunday best.

Angela Patton: A father-daughter dance ... in prison https://www.youtube.com/watch?v=vrl5PFB35Ec  14;27 I was in suit and tie, my Sunday best as my mom called it. 　
Mark Cuban: How I Became a Billionaire

参考リンク
http://bridge-english.blogspot.jp/2016/03/dress-to-nines.html  dress to the nines 正装する

練習問題解答
b-2402 Sunday best
b-4961 in your holiday best