noun

1. The lower of two hands, the hand under the work.

   “Your underhand should be entirely under the quilt.”

verb

1. To toss or lob with an underhand movement.

2. To trick, deceive or gull.

3. To excavate downward in successive steps or horizontal slices while positioned above on unbroken ore.

adjective

1. Secret; clandestine

2. (by extension) dishonest and sneaky; done in a secret or sly manner

3. (in various ball games, of a ball) thrown (etc.) with the hand brought forward and up from below

Synonyms: underhanded, underarm

adverb

1. With an underhand movement

2. In a sly, sneaky or secret manner

Synonyms: underhandedly