Wiktionary
blow upon
vb. 1 To defame, discredit; make someone the subject of a scandal. 2 (context informal dated English) To inform against.
Usage examples of "blow upon".
In the space of a single heartbeat Galen was on him, raining blow upon blow upon him in a mindless fury.
He managed to get in a blow upon his opponent's nose, and this began to bleed.
After years of muddy inefficiency, of contentedness with the second-rate and the dishonest, that flame astoundingly bursts forth, from a hidden, unheeded spark that none had ever thought to blow upon.