You know what it looks like… but what is it called?
TAKE THE QUIZ“one knows”
The following 5 entries include the term one knows.
before one knows it
idiom: very quickly or soon
for all one knows
idiom—used to say that one has little or no knowledge of something
for aught one knows
idiom: for all one knows : one does not know
if one knows what's good for one
idiom: if a person wants to avoid trouble, problems, etc.
not that one knows of
idiom—used in answer to a question to say that someone thinks the answer is no