Originally 'local strongman/tyrant' — a land-owning bully. During land reform the slogan 打土豪，分田地 ('bring down the landlords, redistribute the land') was central. Around 2013 it was revived as internet slang for gaudy new-money types.
culture
The meme phrase 土豪，我们做朋友吧 (2013) cemented the modern meaning: rich but lacking taste — Chinese 'tacky nouveau riche'. Often paired with 金 (gold) as in 土豪金, the 2013 gold iPhone 5s color.
