1. not to mention - Adverb
2. not to mention - Conjunction
much less
Source: WordNetWhat was life worth, anyway, if you had to sit around remembering not to mention this, that, and the other thing because someone else might be upset? Fritz Leiber
That sounds terrific. Just you, your comatose wife, your shell-shocked son, and you daughter who hates your guts. Not to mention that your two kids may be in love with each other. Yeah, that sounds like a perfect family reunion. Cassandra Clare
[Napoleon has now] surpassed...Alexander & Caesar, not to mention the great advantage he has over them in the Cause he fights in. Charles James Fox
The evil effect of science upon men is principally this, that by far the greatest number of those who wish to display a knowledge of it accomplish no improvement at all of the understanding, but only a perversity of it, not to mention that it serves most of them as a tool of vanity. Immanuel Kant
Everyone is entitled to commit murder in the imagination once in a while, not to mention lesser infractions. Thomas Nagel
Mozart has written opera, symphony, sacred and chamber music - not to mention his piano and violin concerti. Neville Marriner