TO SAY NOTHING OF

Without ever needing to speak of; in addition to; besides. - Used to add something to what you have said or explained. * /Dave is handsome and smart not to mention being a good athlete./ * /They have three fine sons, not to speak of their two lovely daughters./ * /Sally takes singing and dancing lessons to say nothing of swimming and tennis lessons./ Compare: LET ALONE, TO SPEAK OF.