sledgehammer
Concise Oxford English Dictionary © 2008 Oxford University Press:
sledgehammer/ˈsleʤhamə(r)/
▶noun
- 1 a large, heavy hammer used for breaking rocks, driving in posts, etc.
- 2 [as modifier] very powerful, forceful, or unsubtle: sledgehammer blows.
'sledgehammer' also found in these Oxford entries:

