When combined, 斗争 (dòuzhēng) creates a compound word that intensifies the meaning of conflict. It's not just a fight (斗) or a dispute (争), but a full-blown struggle that requires sustained effort and resolve.
The cultural weight of 斗争 is immense and inseparable from 20th-century Chinese history. During the Maoist era (1949-1976), 阶级斗争 (jiējí dòuzhēng - class struggle) was a cornerstone of political ideology. It was the belief that society was fundamentally divided into opposing classes (e.g., the proletariat vs. the bourgeoisie) that were locked in a constant, necessary struggle. This wasn't just a theory; it was a call to action that fueled political campaigns, public “struggle sessions” against perceived enemies, and sweeping societal change. Because of this history, 斗争 carries a strong political and ideological flavor that is absent from the English word “struggle.” Comparison to a Western Concept: Compare 斗争 (dòuzhēng) to the American concept of “the grind” or “the hustle.” While both imply hard work against adversity, “the grind” is typically individualistic, often focused on personal career or financial success. 斗争, on the other hand, is frequently collective and ideological. Its historical context is about struggling for a cause (the revolution, the nation, the party) or against a defined enemy (corruption, imperialism, poverty). While you can have a personal 斗争 (e.g., against cancer), the word's default setting is larger and more serious than a personal “hustle.”
While the intense, all-encompassing “class struggle” is a thing of the past, the word 斗争 is still very much in use, primarily in formal and serious contexts.
The connotation is almost always serious and implies a high-stakes conflict. You would never use it for trivial matters.