This word comes to you as two bits glued together awkwardly, or like an overstuffed sack. Originally it was in fact two separable words, as in “He vouched it safe on us.” And these words have something of an aesthetic contrast. Vouch has that /v/, be it virtuous or vile, that kneels the upper teeth onto the lower lip, along with clear echoes of ouch, grouch, pouch, slouch, and couch. Safe is a soft word, a word to sigh as one says it, those voiceless fricatives like down pillows. And yet the final /f/ is the same gesture as the opening /v/, but voiceless. The middle affricate and fricative have nearly the same place of articulation but different manner. The vowels are opposed: the first (/aU/) starts just back of the middle and moves up and back, with lip rounding, while the second (/eI/) starts ahead of middle and moves up and front with no rounding. An odd couple indeed.
And it might even seem a basically Anglo-Saxon word if you didn’t know better. Two homey monosyllables tacked together, nothing fancy… But your first clue should be that v: /v/ was not a separate phoneme in Old English, just a positional variant of /f/, and most places you see it have come to us from French or elsewhere. Indeed, vouch comes from Latin vocare “call”, and safe comes from Latin salvus “uninjured, healthy”. So this word casts off its humble beggar cloak to reveal itself as a nuncio from Latium! It has deigned to assume this more common form, and now we are vouchsafed a glimpse of its true self. And that’s what vouchsafing is: intransitively, deigning or condescending; transitively, granting or permitting as a favour, by grace. A person may only vouchsafe if he or she is of higher status.
One may use this word to address a high personage or deity, as in a prayer – perhaps William McKinley’s “Our earnest prayer is that God will graciously vouchsafe prosperity, happiness, and peace to all our neighbors, and like blessings to all the peoples and powers of earth,” or perhaps the Baha’i prayer that begins “Vouchsafe unto me, O my God, the full measure of Thy love and Thy good-pleasure.” Or, as a writer, like W.E.B. Du Bois, one may plead, “Hear my cry, O God the Reader; vouchsafe that this my book fall not still-born into the world-wilderness.”
On the other hand, one may use it to elevate a more ordinary person, perhaps in Walt Whitman’s words:
Let us twain walk aside from the rest;
Now we are together privately, do you discard ceremony,
Come! vouchsafe to me what has yet been vouchsafed to none – Tell me the whole story,
Tell me what you would not tell your brother, wife, husband, or physician.
One might even say that this word is not in the main about vouching someone or something safe, but rather about getting a voucher into the safe that is a person’s guarded dignity or vulnerability. When we grant someone a favour or give them a special glimpse, after all, it is like opening a door in our suit of armour. But in that speaking, that opening up, that hole, we show ourselves whole by making ourselves whole – uninjured, healthy; and, from the other side, the invocation, we are allowed into the safe and we are allowed to be safe. But without ceremony, you understand – slumming, a kind of kenosis.
Thanks to Roberto De Vido for suggesting vouchsafe.