not a few

[marco_on_the_grassland]

In Japanese English grammar books, the phrase "not a few" is generally described as meaning "a large number," and high school students are still taught this way. However, about twenty years ago, a native English speaker pointed out to me that "not a few" does not mean "a large number" (it only negates "a few"). If you are requested to describe "a large number" using the word "few" (though there woud be a lot of better ones if you do not need to use "few"), you should use "more than a few". "Especially never use it as a subject." I understand that "more than a few" represents "a large number", but I would like to know the accurate meaning of "not a few", especially whether it NEVER suggests "a large number" in ANY case.
Thank you.

 

[jutfrank]

The phrase is used for understatement, so yes, it is a way to emphasise a significantly large quantity. Perhaps your friend was either unaware of its use as a form of expression, or wasn't able to sense the understatement. Take a look at the examples here:

https://www.collinsdictionary.com/dictionary/english/not-a-few

You can see that it is almost always used as a sentence subject.

I should point out that it's not impossible that there could be a string of words 'not a few' that does not carry the sense of a large number, but it would require a somewhat forced context and wouldn't be considered a use of the phrase as an expression.

 

[emsr2d2]

Note that it's always best to give us a complete example sentence in which you want to (or are querying the) use of a specific string of words. That sentence should also be your thread title.

 

[BobK]

The phrase is used for understatement, so yes, it is a way to emphasise a significantly large quantity. Perhaps your friend was either unaware of its use as a form of expression, or wasn't able to sense the understatement. Take a look at the examples here:

https://www.collinsdictionary.com/dictionary/english/not-a-few

You can see that it is almost always used as a sentence subject.

I should point out that it's not impossible that there could be a string of words 'not a few' that does not carry the sense of a large number, but it would require a somewhat forced context and wouldn't be considered a use of the phrase as an expression.

Note that @jutfrank (perhaps intentionally?) demonstrated the same sort of understatement. His 'not impossible' implies 'perfectly possible - and in some cases certain' (which is why @emsr2d2's advice is important).