Interrogative Pronouns

Someone's unplugged your charger and walked off with it. You spin round and demand: "Who took my charger?" That little word who is doing something clever — it's standing in for a person you can't name yet. You don't know the answer, so you use a word that holds the answer's place until someone owns up. Words that do that job are called interrogative pronouns — a fancy name for a small, familiar gang: who, whom, whose, which and what. ("Interrogative" just means asking — same root as interrogate.)

What they actually do

An ordinary pronoun stands in for a noun you already know — she, it, them. An interrogative pronoun stands in for a noun you don't know yet: the answer. Ask "What's for dinner?" and what is holding the place until the answer — pasta — turns up to fill it. That's why they count as pronouns: they're placeholders for the missing piece of a sentence.

The five, one at a time

• who — asks about a person, doing the action: Who scored?
• whom — the same, but for a person on the receiving end: Whom did you ask? (more on this below — don't panic).
• whose — asks who something belongs to: Whose bag is this?
• which — asks you to pick from a known set: Which is yours — the blue one or the black one?
• what — asks openly, usually about a thing: What happened?

The difference between which and what is the size of the field. Which means "choose from these few"; what throws it wide open. Which subject do you prefer? (from your timetable) vs What do you want to be one day? (anything at all).

Picking the right one matters more than it looks. The question word quietly decides what kind of answer comes back — a person, a thing, an owner, or a choice. Ask What broke it? and you're expecting an object; ask Who broke it? and you're expecting a name. Choose the wrong one and you get a blank look instead of an answer, so it's worth a half-second's thought before the words leave your mouth.

Careful: the same word can be a determiner

Here's the first thing that trips people. Which and what only count as pronouns when they stand alone, holding the place of the answer:

Which do you want? · What did you break?

The moment you put a noun straight after them, they stop being pronouns and become interrogative determiners — little pointing words attached to a noun, exactly like the or my:

Which pen do you want? · What time is it?

Same word, two jobs. Alone = pronoun (it is the missing thing). With a noun = determiner (it's just pointing at the noun). You don't need to label it every time — just notice whether it's standing alone or leaning on a noun.

The other trap: asking vs joining

Who, whom, whose and which lead a double life. When they ask a question, they're interrogative pronouns:

Who waved at us?

But the very same words also turn up joining two ideas together, where they don't ask anything at all:

the boy who waved at us

That second job is a different word class — relative pronouns — and it's worth a look once this page clicks. The quick test: if the word is launching a question (and there's usually a question mark coming), it's interrogative. If it's quietly gluing extra detail onto a noun, it's relative.

Watch out

whose vs who's. These sound identical and cause endless red pen. whose is the belonging question-word; who's is just a short way of writing who is (or who has).

• ✗ Who's coat is this? → ✓ Whose coat is this? (you're asking who it belongs to)
• ✓ Who's coming? → this one's right — it means who is coming?

Quick test: if you can swap in who is and it still makes sense, you want who's. If you can't, you want whose.

And that whom. Here's the honest truth, the same as everywhere else on this site: whom is the version for a person on the receiving end (Whom did you invite?), but almost nobody uses it in everyday speech, and who is completely fine — Who did you invite? If whom ever feels stiff, just use who and move on.

Quick check

1. Name the interrogative pronoun: Whose turn is it?

2. Pronoun or determiner? What film are we watching?

3. Fix it: Who's phone keeps buzzing?

4. Asking or joining? the teacher who marked my essay

Where next

• What Is a Pronoun? — where all the pronoun types fit together.
• Relative Pronouns: who, whom, which, that — the same words doing their other job: joining, not asking.
• Word Order in Questions — how the rest of the question lines up behind the question word.

You've used these words to ask questions your whole life. All that's new is the name — and the one handy habit of checking whether a word is asking, pointing at a noun, or joining. Spot the job, and the rest looks after itself.