blow something sky-high
blow (something) sky-high
1. Literally, to destroy something through an explosion. The tanks blew the enemy fortress sky-high.
2. To undermine or negate something completely. I thought I had finally discovered the problem with our experiment, but, when we tested it, the results blew my theory sky-high. Bob was considered for the promotion, but he blew that idea sky-high when he came in late to work each day this week.
See also: blow
blow something sky-high
If someone or something blows someone's plan or intention sky-high, they cause it to fail completely. If Diana breathes a word of this to Mills, it could blow the whole scheme sky-high.