not to say

not to say

As well as; in addition to being. Used to indicate a stronger, more emphatic, or more candid description to what has just been written or spoken of. I think it would be an incredibly ill-advised, not to say downright foolish, not to accept his offer at this point in time. His behavior is boorish, not to say contemptible.
See also: not, say
References in classic literature ?
Don't you know it's a terrible wicked thing not to say your prayers every night?
I replied; and even if they are not, but only appear to be so to the person who is asked, ought he not to say what he thinks, whether you and I forbid him or not?
But it was very difficult for him not to say more, to tell her nothing but that.
Ah, it's as well not to say that, though; for you'd pass for a good deal older, and age tells well in business.
Hatfield; who, before the other's arrival at Horton, had now and then paid him a visit; on which occasions he would always insist upon having the cottage-door kept open, to admit the fresh air for his own convenience, without considering how it might injure the sufferer; and having opened his prayer-book and hastily read over a part of the Service for the Sick, would hurry away again: if he did not stay to administer some harsh rebuke to the afflicted wife, or to make some thoughtless, not to say heartless, observation, rather calculated to increase than diminish the troubles of the suffering pair.
and if so, you may dismount and safely reckon upon any quantity of sleeplessness under this roof for a twelvemonth, not to say for a single night.
But Zarathustra came not to say unto all those liars and fools: "What do YE know of virtue
Of course Shelley's mind was full of the sanctity of the moment, and indignant that "the hour for which the years did sigh" should thus be broken in upon by vulgar revelry; but while we may sympathise with his view, and admit to the full the sacredness, not to say the solemnity, of the marriage ceremony, yet it is to be hoped that it still retains a naturally mirthful side, of which such public merriment is but the crude expression.
I thought-- you promised--you were not to say such things today.
To say that a word has a meaning is not to say that those who use the word correctly have ever thought out what the meaning is: the use of the word comes first, and the meaning is to be distilled out of it by observation and analysis.
But then'--and here was the vexation--'how came it to be that man; how comes he to have this influence over her; how came she to favour his getting away from me; and, more than all, how came she not to say it was a sudden fright, and nothing more?
What nonsense not to say it Arthur--Doyce and Clennam--easier and less trying to me than Mr Clennam--when I know it and you know it too and can't deny it.
He made up his mind that he would go to the shop every day; it was obvious that he had made a disagreeable impression on her, but he thought he had the wits to eradicate it; he would take care not to say anything at which the most susceptible person could be offended.
I did not make the acquaintance of Thackeray's books all at once, or even in rapid succession, and he at no time possessed the whole empire of my catholic, not to say, fickle, affections, during the years I was compassing a full knowledge and sense of his greatness, and burning incense at his shrine.
Mrs Nickleby looked very grand, not to say contemptuous, at this humiliating proposal; and, turning to the old gentleman, who had watched them during these whispers with absorbing eagerness, said: