underhand

About 0.23 uses per million words.

Meaning

1. adjective Secret; clandestine.
2. adjective Dishonest and sneaky; done in a secret or sly manner.
3. adjective Thrown (etc.) with the hand brought forward and up from below.
4. adverb With an underhand movement.
5. adverb In a sly, sneaky or secret manner.
6. verb To toss or lob with an underhand movement.
7. verb To trick, deceive or gull.
8. verb To excavate downward in successive steps or horizontal slices while positioned above on unbroken ore.

Similar words

sneaky corrupt crooked underarm insidious devious fraudulent deceitful deceptive sneak

Often followed by

way and dealings means methods dealing manner to work