stun 
(stŭn)
(stŭn)tr.v. stunned, stun·ning, stuns
1. To daze or render senseless, as by a blow or loud noise.
2. To stupefy, as with the emotional impact of an experience; astound.
n.
A blow or shock that stupefies.
[Middle English stonen, Old French estoner, from Vulgar Latin *extonāre : Latin ex-, ex- + Latin tonāre, to thunder; see (s)tenə- in the Appendix of Indo-European roots.]