/ ˌvaʊtʃˈseɪf; NAmE / verb
vouchsafe sth (to sb) ( old-fashioned or formal ) to give, offer or tell sth to sb, especially in order to give them a special advantage :
[ vn ]
He vouchsafed to me certain family secrets.
[also v that , vnn , v speech ]
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WORD ORIGIN
Middle English : originally as the phrase vouch something safe on someone, i.e. warrant the secure conferment of (something on someone) .