Definitions
1.verbSway unsteadily, reel, or totter.
2.verbDoubt, waver, be shocked.
3.verbHave multiple groups doing the same thing in a uniform fashion, but starting at different, evenly-spaced, times or places (attested from 1856).
4.nounThe motion of one who staggers.
5.nounThat which staggers something or somebody.
6.nounIn animation, the repetition of a sequence of frames to show struggling effort
7.adjectiveIncredible, overwhelming, amazing."The army suffered a staggering defeat."