In a manner that blanches or causes something to turn white or pale; with a whitening effect.
From 'blanching' (present participle of 'blanch') plus the adverbial suffix '-ly'. A rare adverbial form describing how an action occurs with a blanching quality.
This rare word shows the limits of English productivity—technically we can add '-ly' to almost anything, but 'blanchingly' is so uncommon it hardly appears in real speech or writing.
Complete word intelligence in one call. Free tier — 50 lookups/day.