What it sounds like
Once-off, radio button
This is bad because the user doesn’t know the context of the choice. Once-off what?
What it looks like
<fieldset>
<p>Frequency</p>
<input type="radio" id="once-off" name="repetition" value="Once-off" />
<label for="once-off">Once-off</label>
<input type="radio" id="repeating" name="repetition" value="repeating" />
<label for="repeating">Repeating</label>
</fieldset>