archly

Eats, Shoots & Leavesの著者は英語の学者ではありませんが、編集者の仕事をしていたようです。
At The Listener, where I was literary editor from 1986 to 1990, I discovered that any efforts I made to streamline the prose on my pages would always be challenged by one particular sub-editor, who would proof-read my book reviews and archly insert literally dozens of little commas - each one of which I felt as a dart in my flesh.
...
ferverishly crossing out everything she had added, and writing "STET", "STET", "STET", "STET", "STET", all down the page, until my arm got tired and I was spent.
この後にコンマの使用法には "matter of taste" もあると書かれているのですが、それはともかく私は上の引用文に出てきた "archly" の意味が知りたい。
・Collins Dictionary: in a playful or affectedly roguish or mischievous way ⇒ She looked at me rather archly.
・Merriam-Webster's Online Dictionary: in an arch manner
これだと "arch" の意味も再確認する必要がありますね。
・Oxford English Dictionary: Deliberately or affectedly playful and teasing:
・Etymology.com: 1540s, "chief, principal," from prefix arch-; used in 12c. archangel, etc., but extended to so many derogatory uses (arch-rogue, arch-knave, etc.) that by mid-17c. it acquired a meaning of "roguish, mischievous," since softened to "saucy." Also found in archwife (late 14c.), variously defined as "a wife of a superior order" or "a dominating woman, virago."
引用文の最後に出てきた "STET" については本の中で次の説明がありました。
"The marginal direction to printers "STET" (meaning "let it stand" and cancelling an alteration)"