underhanded

Acting or done in a deceptive, secret, or sly manner; dishonest and sneaky. synonym: secret.

Underhand.

In a sly and secret way.

With an underhand movement.

Underhand.

Not having an adequate supply of hands; short-handed; sparsely peopled.

Underhand; clandestine.

Insufficiently provided with hands or workers; short-handed; sparsely populated; obsolete in this sense, short-handed or understaffed being the preferrred term.

Done by moving the hand (and arm) from below.

Sly, dishonest, corrupt, cheating.