to say nothing of

Conjunction

to say nothing of

1. (idiomatic) used by the speaker to mention another important, usually related, point; an apophasis

   She had already eaten a large lunch, to say nothing of a full cooked breakfast that morning.

   • February 2018, Robert Draper in National Geographic Magazine, They Are Watching You—and Everything Else on the Planet

     Today more than 2.5 trillion images are shared or stored on the Internet annually—to say nothing of the billions more photographs and videos people keep to themselves.