Accidently

[T]he exceptions remind me of an ingenious conjecture respecting Newton: that he was probably a being of a superior order, accidently caged in a human body.

Source: wiktionary

As I arrived at the foot of the hill I overtook two ladies, whom I passed. As I did so, I brushed one of them accidently on the arm.

Source: wiktionary

[W]hich arises from four galaxies at four quite different distances that accidently appear close together in the sky. The second line represents two galaxies close together in space and the other two accidently close in projection, the third line close triplets plus a fourth accidently close in projection, the fourth line two close pairs accidently seen close together in projection.

Source: wiktionary

[R]elayed similar cases but suspected that the rocks were accidently dislodged as the animals fled. […] Hall (1963) considered the same data and concluded that while such behavior might originate accidently during flight or display, […]

Source: wiktionary