UNDERHAND (2)

Un″der‐hand′ (ŭn″dẽr‐hănd′), adv. 1. 1. By secret means; in a clandestine manner; hence, by fraud; unfairly.
Such mean revenge, committed underhand. Dryden. Baillie Macwheeble provided Janet, underhand, with meal for their maintenance. Sir W. Scott. 2. 2. (Baseball, Cricket, etc.) In an underhand manner; — said of pitching or bowling.