Astrology is bogus. So is a bolt that is obviously about to break. So is someone who makes blatantly false claims to have solved a scientific problem. (This word seems to have some, but not all, of the connotations of random -- mostly the negative ones.)
It is claimed that `bogus' was originally used in the hackish sense at Princeton in the late 1960s. It was spread to CMU and Yale by Michael Shamos, a migratory Princeton alumnus. A glossary of bogus words was compiled at Yale when the word was first popularized there about 1975-76. These coinages spread into hackerdom from CMU and MIT. Most of them remained wordplay objects rather than actual vocabulary items or live metaphors. Examples: `amboguous' (having multiple bogus interpretations); `bogotissimo' (in a gloriously bogus manner); `bogotophile' (one who is pathologically fascinated by the bogus); `paleobogology' (the study of primeval bogosity).
Some bogowords, however, obtained sufficient live currency to be listed elsewhere in this lexicon; see bogometer , bogon , bogotify and quantum bogodynamics and the related but unlisted {Dr. Fred Mbogo} .
By the early 1980s `bogus' was also current in something like hacker usage sense in West Coast teen slang, and it had gone mainstream by 1985. A correspondent from Cambridge reports, by contrast, that these uses of `bogus' grate on British nerves; in Britain the word means, rather specifically, `counterfeit', as in "a bogus 10-pound note". According to Merriam-Webster, the word dates back to 1825 and originally referred to a counterfeiting machine.