Underhandedly
Part of speech: adverb
Definition: In an underhanded manner.
Underhand
Part of speech: adverb
Definition: with an underhand movementin a sly, sneaky or secret manner
Part of speech: adjective
Definition: dishonest and sneaky; done in a secret or sly manner(in various ball games, of a ball) thrown etc with the hand brought forward and up from below