wú
negative
Original meaning:
dance
Pictograph of a person dancing, with ox tails or bird feathers hanging from his arms, to pray for rain. Original form of 舞 (dance). The current form is a phonetic loan. The simplified character 无 was adapted from the cursive form of the traditional character 無.
Evolution

Bronze script
Mid Spring and Autumn (~600 BC)
Seal script
Shuowen (~100 AD)
Clerical script
Western Jin dynasty (266-316 AD)Regular script
ModernDefinitions
Sources
季旭昇《說文新證》p.495