To toil means to work extremely hard, usually for a long time, at something difficult or exhausting. When farmers toil in their fields from sunrise to sunset, they're doing backbreaking physical labor: planting, weeding, harvesting. When a student toils over a challenging research paper, they're putting in hour after hour of concentrated effort, writing and rewriting until it's right.

The word carries a sense of struggle and persistence. You might work on a puzzle, but you toil through a massive 2,000-piece puzzle that takes weeks to complete. A construction crew toils to build a skyscraper. A scientist toils for years in a laboratory before making a breakthrough discovery.

Toil can also be a noun, referring to hard work itself: “After years of toil, the inventor finally perfected her design.” Toil represents the kind of determined effort that builds things, solves problems, and achieves meaningful goals.