old left; established left wing
Refers to the traditional, pre-existing leftist movements and ideologies, often contrasted with the New Left (新左翼). Used in political and historical contexts.
See also: 新左翼
The old left often clashed with the New Left.
新左翼 refers to the New Left, a movement that emerged in the 1960s and 70s, often critical of the established left (既成左翼).
Compound of 既成 (kisei, 'established') and 左翼 (sayoku, 'left wing'). The term is used to distinguish traditional leftist groups from newer movements.