1. Underhand; clandestine.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• underminded,
• underfunded,
• underhaned,
• underhande,
• underhandd,
• underhand,
• ynderhanded,
• hnderhanded,
• jnderhanded,
• inderhanded,
• 8nderhanded,
• 7nderhanded,
• underhandeed,
• underhandede,
• undrhanded,
• undehanded,
• underhnded,
• undrehanded,
• unnderhanded,
• underhannded

• underivative,
• understand,
• underdown,
• underling,
• underhandedly,
• underseal,
• undercoated,
• underdone,
• undercharge,
• underlie,
• under way,
• underdevelop,
• understanding,
• understaffed,
• Underdahl,
• underplay,
• underpart,
• undermentioned,
• underhand,
• underbid,
• undermine,
• underived,
• underside,
• understated,
• underdeveloped,
• underworld,
• undergird,
• underachieve,
• undertide,
• understandable,
• undersea,
• underwing,
• underwear,
• undergraduate,
• underground,
• undersign,
• undermanned,
• underhung,
• underwood,
• underspend,
• undersealed,
• underframe,
• underfed,
• undersurface,
• understandably,
• understate,
• underfur,
• underline,
• undertone,
• underhill,
• underage,
• undercoat,
• undergrad,
• under wraps,
• underbred,
• underpin.

The adverb form of "underhanded" is "underhandedly".

The adjective form of the word "underhanded" is "underhanded".

The plural form of "underhanded" is "underhandeds".

The singular form of the word "underhanded" remains the same, it does not change.