the.com/jackhammer

means A handheld pneumatic or hydraulic tool that pounds a chisel-like bit rapidly up and down to break up pavement, rock, or concrete.

from Straightforward compound coinage from 'jack' (a device that does mechanical lifting or forceful work, as in 'jack of all trades' tools like the car jack) plus 'hammer,' describing exactly what it does. The pneumatic version emerged in the 19th century alongside the rise of compressed-air tools used in mining and construction, replacing hand sledges for breaking rock and pavement.