Lexicographers, especially historical ones, are always interested in the way words fall in and out of fashion. But while we spend a lot of time tracing the first usage of a word and trying to figure out its origins, we pay much less attention to when or why a word falls out of common usage.
Why do words cease to be used? For some words, the reason is clear. We no longer listen to gramophones or refer to unmarried women as spinsters. Technologies shift, as do our attitudes. But there are also words that fall out of fashion for no apparent reason. We simply seem to stop using them. For example, it is unlikely you would hear anyone still using the word bonzer these days, although in the early twentieth century it was ubiquitous. While we might still understand what it means, we would be unlikely to use it unselfconsciously, if at all.