Inconvenient folk, those ancient Greeks and Romans. By various roads, bits of their languages have joined ours — and some have brought confusion with them.
Latin had a prefix in-, meaning “not”. So English, like French — the route that brought us many Latin words — has lots of Latin-based negative words such as intact, inept and inevitable. The 17th century invented many like these, though not all have survived. But English also used the Germanic prefix un- to create such words, even from Latin roots: uncertain and unconscious, for example.
A few of these words have both forms. The writers of America’s declaration of independence dithered. Do all men have inalienable rights or unalienable? They opted for unalienable (though believing neither, if the men concerned were black). To make new negatives today, we always go for un- or non- , as in uncool or non-issue. But we still have our inalienable past (that’s today’s usual spelling). And it raises problems.
For Latin also used in- to mean “in”, “into”, “inward” or simply “very”. We’ve borrowed this too, with what one can appropriately call unintended consequences. Will inflammable material burn or not burn? To Britons and Indians, it burns; American (and hence Nato) English sensibly uses flammable for that, and non-flammable for the reverse. But Americans can still be inflamed by inflammatory speeches.
Nor are we helped by the way in- changes before certain letters, as it did in Latin. We write imbue, illogical, imperfect. And indeed ignoble.
On top of those rival varieties of in- , Latin left us both ante- , meaning “before”, and anti-, “against”. No problem if you’re writing or reading (though, to use a Germanic parallel, how many of us never write forbear when we meant forebear, or foregone for forgone). But if you’re speaking or listening? And to our ancestors, this was indeed a problem in writing too: they often wrote ante- when they meant anti-.
Anti- is also ex-Greek. But the Greeks did worse than that for us. They had a preposition ana, meaning “up”, which they also used as a prefix. So do we, in Greek-based words like analyse. But they also had a prefix a-, meaning “not”, which before a vowel becomes an-, and figures in many of our scientific terms. So if a word starts with ana-, which prefix is this? Ana- before some root word that starts with a consonant, or an- before one that begins with the vowel a?
That question is easily answered if the Greek root is fairly recognizable, as in anagram or analogy. This is ana-, “up”. But things aren’t so easy with rarer words. To specialists in classical poetry, anapaest means a foot that goes diddy-dum, a kind of “up-beat”, you might say. But anaemic is not “up-blooded”, it’s “poorly-blooded”. That’s an-, “not”.
What do anabiotic and anaphrodisiac mean? “Pro-life”, but “anti-aphrodisiac”. Anaphylactic shock? “Over-protective” or “anti-protective”? I’ll leave that to you. OK, you won’t meet these words on every street-corner, but it might be nice to be able to recognize their meaning if you did.
English also readily mixes up the Latin “not”, the Greek one and the Germanic one when it feels the need. We use immoral for bad morals, amoral (or, rare but it exists, unmoral) for lack of any morals, anaesthetic in hospitals, unaesthetic in art galleries (and there was once inaesthetic too); moral being of Latin origin, aesthetic of Greek, and un- of neither. But here I make no complaint. The distinctions are useful, and combining one source-language with another is no crime, except to the most uninformed of pedants.