shuō​bu​qīng

cannot say for sure

说不清 說不清 shuō​bu​qīng
cannot say for sure
To be unable to explain something clearly or speak with certainty, often because of a lack of information or the complexity of the situation.
to speak unclearly
To be unable to pronounce words or articulate speech in a way that is easily understood by others.

Frequency

Movie subtitles
2.38 per million appears in 1% of films
Written text
3.41 per million

Sources