left wing
1. adjective Of, concerned with, or belonging to a liberal political position or agenda. (Most often hyphenated and used prenominally.) This is clearly just a left-wing propaganda campaign to distract voters from the real issue at hand. My father is a pretty staunch conservative, so I don't know how he'll take to my left-wing boyfriend. Though I consider myself to be left wing overall, I try to maintain a balanced political opinion.
2. noun The political groups or organizations, or a section or branch thereof, that support or advocate a liberal position or agenda. The left wing has espoused the need for drastic social reform and economic equality in the coming year, but it has not, to date, offered any realistic or lasting measures to implement such change.