/dahrk"lee/ , adv.
1. so as to appear dark.
2. vaguely; mysteriously.
3. in a vaguely threatening or menacing manner: He hinted darkly that we had not heard the last of the matter.
4. imperfectly; faintly.
[ bef. 1000; ME derkly, OE deorclice (in fig. sense only). See DARK, -LY ]