FollowMarch was about prefixes. The un- of uncool, unknowable, unpredicatable, unintelligible, uninhabited, and so forth. Attached to adjectives, un- means not. It also means not when attached to nouns, like undead, uncola, and the great unwashed. But attached to verbs, un- means to reverse the effect of: to undo, untie, unfasten, unbutton. So there are rules for prefixes that are sensitive to the part of speech of the root word.
The same goes for ex-. You can have an ex-spouse or ex-friend or ex-president or be an ex-student or ex-employee. But you can’t ex-marry or ex-friend or ex-employ. Ex- goes with nouns but verbs. There is a grammar to prefixes (all fixes, really) and we call this grammar morphology.
Prefixes can be ambiguous just as words can. Take in-, for example. Semantically in- is sometimes like un- or ex- in words like indescribable, intangible, indefensible, infallible, incredible, inevitable, inept, inability (which is the noun form of unable, oddly). It means not. Of course, sometimes the in- changes its sound shape to homophonize with a following consonant: impossible, improbable, irregular, illegal, but that’s another story.
Sometimes in- just means in. As in indent, income, immigrant, and impediment. This brings us to the words ingratiate and ingrate, two unrelated words that sound like they should be related but aren’t. In ingratiate, you are trying to get in the good graces of someone. But if you are an ingrate, you are ungrateful (there that in-/un- switch again). And so course, this is why words like inflammable as confusing.
Is it not flammable or is it able to burst into flame? Words have an internal structure and if you correctly interpret inflammable as able to burst into flames you are treating the [inflame] as one part and able as added to that: [[inflame] able] if you adopt the other meaning you are putting flame and able together first, then adding in: [in[flammable]]. It’s a natural enough thing to do.
One of my students, by the way, suggested—in jest, I think—that implode meant not explode. It’s an unimpossible analysis, I think. I suppose that infallible could also mean able to fall into. Hmm.
Returning to the realm of the unimpossible, the same ambiguity arises with un- and –able. Things can be undoable, untieable, unbuttonable, and unzippable—able to be undone or not able to be done, etcetera. Not all prefixes mean not, by the way. But a lot do: a- and an-, un-, in-, de-, ex-.
Before we leave prefixes, I should point out the word defixes, that I introduced to refer to prefixes (or suffixes) that get promoted to words, like ex, bi, ism, and ish. A student suggested ishness, which uses the promoted prefix ish as the root. And this can work the other way too: words can be pressed into service as affixes (more next time).
