Turnoff vs. Turn Off
“Turn off” is the two-word phrasal verb for switching something off, leaving a road, or causing loss of interest. The corresponding noun appears as closed “turnoff” in American usage and also as hyphenated “turn-off” in Cambridge.
Use “turn off” as the phrasal verb. Use noun “turnoff” in common American spelling; Cambridge also records the hyphenated noun “turn-off.”
Key details
Choose the right form
| Context | Use | Decision |
|---|---|---|
| verb meaning switch off or cause to stop operating | turn off | Use the two-word phrasal verb. |
| noun in common American spelling | turnoff | Use the closed noun when that spelling fits the variety/style. |
| hyphenated noun spelling | turn-off | Recognize the documented variant rather than treating it as the verb. |
Quick tests
Noun-or-verb test
Is the expression performing a verb job?
If yes: Use “turn off.”
If no: For the noun, “turnoff” is common American spelling and “turn-off” is also documented.
Caveat: Noun spelling varies; the two-word form is reserved for the phrasal verb in this comparison.
Examples
Turn off the monitor before disconnecting the cable.
“Turn off” is the phrasal verb.
The long detour was a real turnoff for visitors.
“Turnoff” is a noun in common American spelling.
The guide uses turn-off as its preferred noun spelling.
The hyphenated noun is also documented.
Further guidance
Core difference
Use “turn off” when the expression is a verb; use the noun form “turnoff”/“turn-off” when naming a road exit or something that causes loss of interest.
Fast Test
If you can inflect the action as “turned off” or “turning off,” use the spaced verb.
Usage Boundary
Noun spelling varies: Cambridge shows closed “turnoff” in its American dictionary and hyphenated “turn-off” in other entries, so do not label one noun spelling universally wrong.
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.
- turnoff — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Direct American-dictionary evidence for closed noun turnoff in road-exit and loss-of-interest senses.
- turn off / turn-off — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Direct dictionary evidence for two-word phrasal verb turn off and hyphenated noun turn-off.