Hi, all. 40 years ago, whilst struggling to learn Latin, I was told that "ad hoc" translates into English as "for the purpose". An ad hoc committee, for example, would be one that was formed for a specific purpose.
In the 40 years that have since elapsed I've never heard the phrase used to mean that, I've only heard it used to mean random, unplanned, or casual.
How does a phrase, where there is no question as to its origin or precise meaning, suddenly come to mean something that is almost the direct opposite?
It's not unheard of- clinical originally had a meaning closer to bedside manner (Webster's 1828 definition has no trace of the antiseptic/unemotional meanings it acquired), literally is often used to mean anything other than the dictionary definition of the word. To coin a phrase is being used increasingly as a way of introducing a cliché, a direct opposite from the original meaning and not even in a foreign language.
(I know no Latin, but I have seen it translated as 'to this')