Left-wing

noun
1.
members of a liberal or radical political party, or those favoring extensive political reform.
2.
such a party or a group of such parties.
3.
the part of a political or social organization advocating a liberal or radical position.
noun
1.
(often capital) the leftist faction of an assembly, party, group, etc; the radical or progressive wing
2.
the units of an army situated on the left of a battle position
3.
(sport)

adjective
4.
of, belonging to, or relating to the political left wing
n.

also (as an adjective) left-wing, 1871 in the political sense (1530s in a military formation sense), from left (adj.) + wing (n.). Related: Left-winger.

A descriptive term for liberal, radical, or revolutionary political views, particularly the view that there are unacceptable social inequalities in the present order of society. Communists and socialists, as well as moderate liberals, come under the term left-wing. Left-wing groups are sometimes known collectively as the Left. (Compare right-wing.)

A descriptive term for an individual or a political faction that advocates liberal, radical, or even revolutionary policies, usually in favor of overcoming social inequalities. In the United States, left-wing groups generally support federal social welfare programs designed to open opportunities to all citizens. (Compare right-wing.)

Note: Although both major political parties in the United States have left-wing factions, left-wing policies are usually associated with the Democratic party.

The liberal or radical faction of a political group, as in Many consider him a leader of the Democratic Party’s left wing. This expression originated in the seating practice of European legislatures, whereby those holding liberal views were assigned to the left side of the house. [ First half of 1800s ]