not to mention
idiomPart ofmention
not to mention — idiom
1. used to add extra information that strengthens or emphasises what you have just
1.idiom
Definition
used to add extra information that strengthens or emphasises what you have just said, often something that is equally important or even more so
Example
The apartment is small and dark, not to mention the terrible noise from the street.
Reuben already speaks French and Spanish fluently, not to mention his excellent Mandarin.