thwart

Thwart is a word with both verb and noun uses in English. As a verb, thwart means to prevent someone from achieving a goal or to foil, hinder, or oppose their plans. It can also mean to cross or block something by placing it across another object, especially to obstruct a passage. The noun thwart refers to a crosspiece or seat that runs across a boat’s width, providing support for rowers; it can also denote any transverse brace or crossbar in a framework.

In nautical contexts, a thwart is a principal crosspiece of the open boat, typically fixed across the hull and used as seating. The plural thwart(s) can be applied to multiple crosspieces within a boat.

Etymology traces thwart to senses of crossing or lying across in Old English and related Germanic languages; the figurative sense of hindering developed in the Middle English period and has since become common in modern usage. The word’s crosswise meaning underpins both the literal nautical sense and the broader figurative uses.

Synonyms for the verb include hinder, obstruct, impede, foil, and frustrate; the nautical meaning remains distinct from these figurative uses. Thwart is widely used in everyday language to describe actions that block or derail plans, while the boat-related sense remains common in nautical writing and discussion.