‘Thwart’ encompasses two opposing meanings
A reader asked about the origins of thwart, which has two sets of meanings that are at odds. On one hand, to thwart something is to hinder or prevent it; in older uses, though, thwart implied crosswise motion or position. English has several other words that occupy both of these semi-opposed semantic fields, with meanings converging on “to block” and “to span.”
English borrowed thwart from Old Norse around the 12th century. It seems to have had a root sense of “across” or “going back and forth,” which blossomed into a range of similar meanings. It could mean “to traverse” – Shakespeare has a character “thwarting ... the seas.” To thwart also meant “to place something across”: In 1609 building a bridge over a river was described as “thwarting a bank.” Likewise, the preposition athwart means “across,” as with a bar placed “athwart the door” (1470). Since 1736, the noun thwart has referred to the pieces of wood or metal that reinforce the hulls of canoes and boats.
A key effect of placing one thing across another, though, is blockage, and this is the semantic field thwart occupies now. Overwhelmingly today, thwart means to get in the way, or as the Oxford English Dictionary puts it, “to foil, frustrate, balk, defeat.”
The connection between laying/lying across and blocking is easy to visualize. What’s surprising is how many common words share it. Cross itself is the most obvious parallel. It also includes spanning and hindering – the bridge allows people to cross the river; the cartoon villain warns the hero “Don’t cross me!”
Today the primary meanings of traverse align with the spanning side. According to Merriam-Webster, they are “to go or travel across or over” and “to lie or extend across.” As a noun, traverses are crosspieces that extend from one side to the other, including ceiling rafters, door lintels, and so on. Most of its earliest senses (14th to 15th century) are of the obstructive variety. A traverse was also a screen or curtain positioned across a room, dividing it; traverses were military earthworks dug to form a barrier to enemy fire. As a verb, it indicated “to deny (an allegation) formally; to dispute or challenge.”
Balk has a similar range of senses. In Old English, it was a heap of earth, a ridge between two plowed furrows. By 1400, a balk was an exposed roof beam that stretched from wall to wall. By 1589, “to balk” meant to “place a balk in front of someone,” i.e., hinder or thwart. If you hindered yourself, so to speak, you hesitated or stopped short and refused to go on, and this is balk’s primary sense today. (“She balked at the idea of coming up with a better closing sentence.”)
