Searching, a.
Exploring thoroughly; scrutinizing; penetrating; trying; as, a searching discourse; a searching eye. "Piercing, searching, biting, cold." Dickens. -- Search"ing*ly, adv. -- Search"ing*ness, n.
Shades of meaning
Fernald has no entry of its own for searching; he lists it under inquisitive.
He lists it without comment; the entries above explain its neighbors.