1. (adj)underhand, underhanded, underarm with hand brought forward and up from below shoulderlevel "an underhand pitch"; "an underhand stroke"
2. (adj)sneaky, underhand, underhanded marked by deception "achieved success in business only by underhand methods"
3. (adverb)underhandedly, underhand slyly and secretly "Mean revenge, committed underhand"- John Donne; "oldline aristocratic diplomats underhandedly undermined the attempt...to align Germany with the Western democracies"- C.G.Bowers
4. (adverb)underarm, underhand with the hand swung below shoulderlevel "throwing a ball underarm"