Lethologica, noun:the affliction of not remembering the right word for the thought you are trying to express.

USAGE:He was usually never at a loss for words, but right in the middle of an important interview, he suffered a crippling bout of lethologica.

Lethologica happens to everyone – yes, even me! How many of us have gone through that awful feeling when you think of something you know well and wish to convey precisely, to the person you are speaking to, but the word for it escapes you? Lethologica is not the same as simply mixing up similar-sounding words, as when people say “reticence” when they mean “reluctance”, a common error. It’s when the word you want is trembling at the tip of your tongue but your mind is simply unable to dredge it up from all the many times you have heard or used it before.

Lethologica is derived from the Ancient Greek words lethe, or forgetfulness, and logikos, which means “of or relating to thought or reason”. The affliction was first identified as a disorder by the famous Swiss psychiatrist Carl Jung in 1913. But it’s really far too common a problem to be elevated to the medical textbooks. It’s also not incurable – usually you struggle to remember the right word, and the harder you try, the more elusive it gets. (In the worst cases, that can lead to loganamnosis – when the sufferer from lethologica is so obsessed with trying to remember the word that she couldn’t recall, that she’s unable to pay attention to the rest of the conversation.)

But just when you have parted from the friend you were speaking to – that’s when the words pops up, miraculously and frustratingly. Or worse, just when you are falling asleep, the mind goes ”Eureka! That’s it! The word for not remembering the right word – it’s lethologica!”