in one fell swoop

[in one fell swoop] or [at one fell swoop] {adv. phr.} 1.{literary} In one attack or accident; in one bad blow.

Themillionaire lost his money and his friends at one fell swoop.

2. Atone time; at the same time.

Three cars drove into the driveway, andMrs. Crane's dinner guests all arrived at one fell swoop.