Rot comes from Old English rotian ('to decay, putrefy'), from Proto-Germanic *rutāną, from Proto-Indo-European *(s)reud- ('to rot'). The 'nonsense' sense is 19th-century slang. The historical chain includes Old English rotian and Proto-Germanic *rutāną. Older glosses in the chain include "to decay, putrefy", "to rot", and "nonsense", which help explain the semantic range of the modern word. Morphologically, rot is best read as borrowing, yielding an English verb and noun shaped by both form history and later usage. In current English it functions as a verb and noun, with the sense "to decay or decompose; the process or state of decay; nonsense". English derivatives include rotten, rotting, rotted, and rotter; related forms include rotten and ret. The result is an English verb and noun whose etymology preserves the older forms while supporting the word's specialized modern meaning.