C2adverbformalnatureconflict
US/ˈtretʃ.ər.əs.li/
UK/ˈtretʃ.ər.əs.li/
in a dangerous way that is hard to notice, or in a way that betrays trust
In context
The road was treacherously icy after the overnight frost.
He treacherously sold the secret plans to a rival company.
The path climbs treacherously close to the edge of the cliff.
Words that go with treacherously
adverb + adjective
- treacherously icyThe pavements were treacherously icy this morning.
- treacherously steepThe slope became treacherously steep near the top.
- treacherously closeThe boat drifted treacherously close to the rocks.
- treacherously slipperyThe floor was treacherously slippery after the rain.
- treacherously calmThe sea looked treacherously calm before the storm.
adverb + verb
- treacherously betrayHe treacherously betrayed the friend who had trusted him.
Common mistakes
Incorrect:
The road is treacherous icy.Correct: The road is treacherously icy.