the.com/lefty

means A left-handed person — or, in sports and politics, someone whose stance (a pitching arm, a political lean) sits on the left side of normal.

from Simple compounding: 'left' plus the informal '-y/-ie' suffix that English loves to slap onto adjectives to make casual nicknames (same move as 'righty,' 'softy,' 'lefty' in boxing slang for a left hook). 'Left' itself traces back to Old English 'lyft,' which already carried a whiff of 'weak' or 'worthless' — a sign of how long left-handedness got side-eyed by a right-leaning world. The word jumped into sports and political slang (a 'lefty' pitcher, a 'lefty' politician) by the 19th–20th century, riding that same suffix.