Meaning

noun (American football) defensive players try to break through the offensive line

noun a swift and violent military offensive with intensive aerial bombardment

verb attack suddenly and without warning

originSpecific use of blitz. The Blitz was in truth not a blitzkrieg, which is a rapid ground offensive based on superior tank forces. However, the word was current at the time for the successful German campaigns in Poland and France, and was transferred to the attacks on Britain, perhaps by association of Blitz (“lightning”) with the bombings.

Etymology from Wiktionary, CC BY-SA 3.0