IPA: /ˈɑːr.tʃli/
KK: /ˈɑrʧli/
In a playful or teasing way, often with a hint of slyness or mischief.
She smiled archly, knowing she had a clever plan in mind.
Archly → It is formed from "arch" (from Old French *arche*, meaning chief or principal) and "-ly" (meaning in a manner of). The word "archly" means in a chief or principal manner, often implying a playful or mischievous tone.
Think of someone acting in a 'chief' or 'principal' way ('arch') — that's why archly means behaving in a playful or mischievous manner.