a.
adv.
Such mean revenge, committed underhand. Dryden. [ 1913 Webster ]
Baillie Macwheeble provided Janet, underhand, with meal for their maintenance. Sir W. Scott. [ 1913 Webster ]
In modern usage, the sense is usually negative. [ PJC ]
a.
Norway . . . might defy the world, . . . but it is much underhanded now. Coleridge. [ 1913 Webster ]
adv. In an underhand manner. [ 1913 Webster ]