leeway

Leeway is a compound of lee (the sheltered side, the side away from the wind) and way (movement, progress). In sailing, leeway is the lateral drift of a vessel to leeward — downwind — of its intended course. Every sailing vessel makes leeway. A square-rigged ship sailing close to the wind might drift five to fifteen degrees off its heading. A modern racing yacht makes two to four degrees. No sailing vessel can completely eliminate leeway. The wind always pushes you sideways.

Navigators had to account for leeway when plotting courses. If you aimed at a destination without correcting for leeway, you would arrive downwind of your target — possibly by miles. Experienced navigators learned the leeway characteristics of their ships and added corrections to their compass headings. The ability to estimate leeway accurately was a survival skill. Underestimate it, and you miss your port. Overestimate it, and you waste time sailing too far upwind.

The figurative meaning — room for error, margin for maneuver — appeared in English by the early nineteenth century. 'Give me some leeway' means 'give me room to drift without punishment.' The metaphor is precise: leeway in sailing is the gap between the intended course and the actual course. Leeway in conversation is the gap between the ideal and the acceptable. Both assume that perfection is impossible and that drift must be accommodated.

The word has no synonym that carries the same nautical authority. 'Slack,' 'latitude,' and 'margin' come close, but leeway implies specifically that the drift is caused by external forces, not by the person drifting. A ship makes leeway because the wind pushes it. A person needs leeway because circumstances push them. The word assigns responsibility to the wind.