Runoff vs. Run-off vs. Run Off
“Runoff” is a noun used for an additional election and for flowing water or liquid; Cambridge also records “run-off.” “Run off” is a separate two-word phrasal verb with senses including leaving suddenly and producing copies.
Use “run off” for the verb. For the noun, “runoff” and “run-off” are both documented.
Key details
Choose the right form
| If you mean / need | Use | Why |
|---|---|---|
| an election round or flowing liquid | runoff / run-off | Both noun spellings are documented. |
| an action such as leaving suddenly or producing copies | run off | The phrasal verb is written as two words. |
Further guidance
Core difference
Use “run off” when the expression functions as a verb; use the documented noun form for the person, thing, event, result, or modifier.
Fast Test
If tense or inflection works naturally—such as a past or -ing form—you are using the verb and should keep “run off” as separate words.
Variant Boundary
Cambridge records both “runoff” and “run-off” as noun spellings while “run off” remains a two-word phrasal verb.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- RUNOFF — English meaning (opens in a new tab)Cambridge Dictionary · Noun “runoff,” with “run-off” also documented
- RUN OFF — English meaning (opens in a new tab)Cambridge Dictionary · Two-word phrasal verb “run off” for leaving, printing, and related verb senses