Merriam-Webster Collegiate Dictionary - sledgehammer

 I. noun  Date: 15th century a large heavy hammer that is wielded with both hands; also something that resembles a ~ in action  II. verb  Date: 1834  transitive verb to strike with or as if with a ~  intransitive verb to strike blows with or as if with a ~  III. adjective  Date: 1827 marked by heavy-handed directness or hard-hitting force trusting in ~ warfare — C. J. Rolo