mid-15c., "walk unsteadily, reel" (intransitive), altered from stakeren (early 14c.), from a Scandinavian source (compare Old Danish stagra, Old Norse stakra "to push, shove, cause to reel," also "to stumble, stagger," perhaps literally "hit with a stick," from Proto-Germanic *stakon- "a stake," from PIE *steg- (1) "pole, stick." Cognate with Dutch staggelen "to stagger," German staggeln "to stammer." Transitive sense of "bewilder, amaze" first recorded 1550s; that of "arrange in a zig-zag pattern" is from 1856. Related: Staggered; staggering.
<a href="https://www.etymonline.com/word/staggering">Etymology of staggering by etymonline</a>
Harper, D. (n.d.). Etymology of staggering. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/staggering