Conjunctive Adverbs vs Conjunctions

You've just finished your history essay, rather pleased with the last line: The Romans built roads across Britain, however they left in the fifth century. Back it comes with a red circle round that comma: "comma splice — fix!"

You stare at it, a bit offended. However was doing exactly the job but would have done. Why is one fine and the other apparently a crime? Here's the thing. Words like however, therefore, and meanwhile feel like joining words, but English quietly treats them as a different kind of word from and, but, and because. They're not conjunctions at all. They're conjunctive adverbs, and that small difference in category is exactly why the punctuation rules change.

Two families of "linking" word

Conjunctions are true joiners. They glue clauses together, and they're strong enough to do that with nothing more than a comma. You'll already know the coordinating ones — and, but, or, so, yet — and the subordinating ones — because, although, when, if.

I was tired, but I kept working. One comma. One sentence. Job done.

Now look at this: I was tired. However, I kept working. However is doing something similar — showing a contrast — but it isn't a conjunction. It's an adverb: a word that comments on a clause rather than legally binding two clauses into one sentence. Because it's not built to do the joining work, it can't be dropped into the gap between two full sentences with just a comma. If you try, you get a comma splice:

• ✗ I was tired, however I kept working.
• ✗ It was raining, therefore we stayed inside.

You've got three safe ways to fix it:

1. A full stop [US: period], starting a new sentence: I was tired. However, I kept working. 2. A semicolon before, and a comma after: I was tired; however, I kept working. 3. Swap in a genuine conjunction: I was tired, but I kept working.

Notice the pattern in options 1 and 2: strong break before the conjunctive adverb, comma straight after it. That little formula — strong break, then adverb, then comma — gets you through nine out of ten sentences. A useful test: cover up the conjunctive adverb and see if both halves stand alone. I was tired. ✅ I kept working. ✅ If both work on their own, the join needs to be strong — a semicolon or full stop, never a lone comma.

The three main words

However — contrast, much like but: The bus was late. However, we still arrived on time.

Therefore — result, doing roughly the job of so: The road was flooded. Therefore, the match was cancelled.

Meanwhile — simultaneous time, often in different places: I was doing my homework. Meanwhile, my friends were at the cinema.

Each one shows up in three positions:

• At the start of a new sentence: I was nervous. However, I did my best.
• After a semicolon: I was nervous; however, I did my best.
• Tucked into the middle of a single clause, framed by commas: The experiment was, however, a complete failure.

That third one is worth pausing on. When however sits inside one clause rather than between two, it's just an ordinary interrupting adverb. There's only one sentence there, so no semicolon is needed — just commas around the interruption, the way you'd bracket off any aside.

Once you notice that all three words follow exactly the same punctuation rules, this whole topic gets simpler. The meaning changes from word to word — contrast, result, timing — but the punctuation logic doesn't.

Watch out: don't assume however, therefore, meanwhile are just posh versions of but, so, while that behave the same way. But, so, while are true conjunctions, comfortable with a single comma; however, therefore, meanwhile are conjunctive adverbs, needing a stronger break.

The mobility test

Here's a neat trick for telling a conjunctive adverb from a true conjunction: try moving it around inside its own clause.

I still found the test difficult, however. I, however, still found the test difficult. However, I still found the test difficult.

All three work. That freedom to roam is a classic trait of adverbs — the same trait you'll recognise from sentence adverbs like unfortunately or clearly. Now try the same trick with a genuine conjunction: I still found the test difficult, but. ✗ That simply breaks. But is welded to the front of its clause and can't be relocated. That fixed position is exactly what marks out a true conjunction.

Style choices

Semicolon or full stop? Both I was exhausted. However, I kept going and I was exhausted; however, I kept going are correct. The difference is rhythm: a full stop gives a clean, definite break; a semicolon keeps the two ideas closer, signalling that the second is a tightly-linked response to the first. Reach for the full stop when you want a clear break, the semicolon when the two ideas genuinely belong together.

Don't stack them. However, therefore, this is clearly the best solution reads as clumsy. Pick the one word that matches the logic and trust it to do the job alone.

One genuine grey area: the word then, meaning "after that," behaves exactly like our three conjunctive adverbs, but you'll see it comma-spliced constantly, even in published writing — "I finished my homework, then I watched TV." Strictly, that's the same error. In practice it's so embedded in relaxed writing that many teachers let it pass in a story, while still expecting the stricter rule in a formal essay.

Watch out: if every other sentence in your essay starts with However, Therefore, or Meanwhile, your writing sounds stiff and mechanical. Mix in plainer conjunctions like but and so, or occasionally just start with the subject.

Quick check

1. Fix the punctuation: I love reading, however I don't enjoy writing essays.

2. Choose the best word: The school trip was cancelled. ___, everyone had to stay in class. (However / Therefore / Meanwhile)

3. Is this correct? If not, rewrite: I was revising, meanwhile my friends were at football practice.

4. Join with however using a semicolon: The science project was difficult. We finished it on time.

5. Does however need a semicolon here? The results were, however, better than we expected.

Where next

• — Coordinating Conjunctions (and, but, or) — the true joiners that only need a comma.
• — Subordinating Conjunctions (because, although, if) — how dependent clauses attach to independent ones.
• — Sentence Adverbs — the wider family of words that comment on a whole clause.
• Semicolons, commas, and full stops [US: periods] — the full story, in the Punctuation pillar.