Colloquial and pejorative — calling someone 二流子 is an insult. Northern Chinese flavor. The term spread nationally during the 1940s Yan'an campaigns to 'reform 二流子' into productive workers.
history
二流 (èrliú) literally 'second-rate / drifting'. The 1940s Communist propaganda campaign 改造二流子 made it a stock political-cultural label for those who wouldn't join collective labor.