Thwart

Thwart \THWAWRT\ , verb;
1. To oppose successfully; prevent from accomplishing a purpose
adjective;
1. Passing or lying crosswise or across; transverse

I love words with kooky spellings like this. I mean, it makes perfect sense within our spelling rules, but it looks cool anyway. It would be even better (not to mention a fantastic Scrabble® word) if it was spelled like the pronunciation guide!

As is to be expected, a word with this kind of spelling definitely comes from the Germanic branch of the Proto-Indo-European tree. According to Etymonline.com:
The word dates to the 12th century and comes from Old Norse þvert ("across"), which was originally the neuter of thverr (an adjective meaning "transverse, across"). Thverr is a cognate with Old English þweorh ("transverse, perverse, angry, cross"), both coming from Proto-Germanic *thwerkhaz. The Proto-Germanic word was altered  from *therkh-, probably because of influences by *thwer- ("to turn"). The original Proto-Indo-European word was *twork- or *twerk-, meaning "twist." The verb definition dates from the mid-13th century.

The letter þ is called a thorn and is a letter that was in several Old and Middle languages in the Germanic family. In English, it eventually gave way to the 'th' digraph. It could either be the 'th' in that (voiced) or this (voiceless). Either way, it's a dental fricative (for those who took a phonetics class in college).

If you are feeling a bit lost in this Proto-Indo-European, Germanic family, etc. terminology, read the Eke post from October 26.

*Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Tuesday, November 2, 2010