Arch (4)

Arch (ärch), a. [See Arch-, pref.] 1. Chief; eminent; greatest; principal.

The most arch act of piteous massacre.

Shak.

2. Cunning or sly; sportively mischievous; roguish; as, an arch look, word, lad.

spoke his request with so arch a leer.

Tatler.