The Little Word That Believes Everything Happens for a Reason

"What did you do that for?"
You have probably said some version of that sentence today, and in saying it you broke a rule you were never taught. A preposition, as its name suggests — the word comes from Latin for "place before" — is supposed to sit in front of something: a noun, a phrase, a target. Yet there it was, "for," dangling off the end of your question with nothing behind it, and neither you nor your listener noticed anything odd. That is the first clue to how strange this word is. Nobody teaches it, everybody uses it, and by most counts it lands in the top dozen most common words in English — a language with hundreds of thousands of words. Ahead of nearly every noun, verb, and adjective you own.
Consider what a single "for" is asked to do over the course of an ordinary day. A mug for coffee. A gift for your mother. Twenty dollars for a haircut. Famous for losing his temper. Gone for an hour. I'm all for it. For a girl her age, she's remarkably calm. For all his effort, he came in last. Each time it is the same word doing a completely different job: naming a purpose, naming a recipient, setting a price, assigning a cause, measuring a duration, declaring an allegiance, conceding a contrast. Open a decent dictionary and the sense list runs to a couple dozen entries, plus an annex of idioms — for good, for now, for once, for the record — in which the word means almost nothing alone and everything in company.
The word also misbehaves in ways that would get a noun fired. It strands itself at the ends of questions, as we have seen: "Who is this for?" "What are you waiting for?" It moonlights as a conjunction — "She said nothing, for there was nothing to say" — a use that now sounds faintly Victorian, better suited to the third chapter of a novel than to a Tuesday afternoon. And it performs its strangest trick in sentences like "It would be unusual for her to arrive early," where "for" somehow welds a person to an action and lets an entire clause squeeze into the subject of the sentence. Show that construction to a learner of English and watch their face. A preposition that can launch a clause is like a coat hook that turns out to be holding up the whole wall.
But the deepest thing about "for" is not its flexibility. It is what the word is for. Of all the jobs it does, the one at its center is purpose — reason, aim, intention. This is the word English uses to bolt meaning onto action. A knife is for cutting; a spare key is for emergencies; a question is for finding out. Ask what any object is for and you are asking about the intention folded into its design. Children ask it constantly — what's that for, what's this for — because they are sorting the world into things-with-jobs, and "for" is the label on the box. Grown-ups keep doing the same thing, only with lives: a job for the money, a degree for the career, a career for the family, everything for something. It is no accident that when English needs to talk about reasons, it reaches for this word. For a reason. For the sake of. For your own good. Even the marriage vow hands the word the weight of a lifetime — for better, for worse, for richer, for poorer — and whatever else those promises commit to, they commit to a "for": a purpose meant to outlast the feeling of the moment.
The word's history explains how it came to carry so much. "For" comes from Old English "for," a close relative of "fore" and "before," and its oldest kinship is with words of position — in front of, ahead of. You can still see the family inheritance in German, which split it in two: "vor" kept the spatial meaning while "für" took on purpose and benefit. English, characteristically, kept everything in one drawer. And the drift in meaning is easy to retrace. To stand in front of something is to be positioned ahead of it. To go ahead of someone is to act on their behalf. To act on behalf of a cause is to do things because of it, or in order to further it. Space becomes service, service becomes cause, cause becomes purpose. The whole movement from the concrete to the abstract — the movement that separates human language from pointing — is folded into four letters.
Naturally, a word this overloaded attracts quarrels. "For free" has been annoying careful writers for the better part of a century: "free," they point out, already means "for nothing," so the "for" is dead weight. The phrase appeared anyway, in American speech, and won, which is usually how these arguments end. There are quieter regional divides, too. An American says "I haven't seen her in three years," while British English leans toward "for three years" — same gap of time, different preposition, no misunderstanding between them. And some idioms have drifted so far from their parts that they mean nearly the opposite of what they appear to say. "For good" means permanently, not virtuously. "For the birds" means worthless. "For crying out loud" is a scrubbed substitute for a blasphemy, everyone knows it, and everyone still says the scrubbed version with real feeling.
Here is a small experiment worth trying. For one day — and there is no way to write about this word without using it constantly, as you may have noticed — count the times it appears in your own speech. You will find not just a word but a ledger: what you are aiming at, whom you are acting on behalf of, what you would defend, what you are still waiting on. A running record of purposes, most of them never consciously chosen, all of them carried by a word small enough to overlook and load-bearing enough that English would visibly sag without it.
And when you reach the end of that day with the tally half-finished and the notebook mostly blank, ask the question the word itself has been waiting all along to put to you.
What are you waiting for?