This originally Australian term was well known in the cricketing world by the early 1980s. It refers to a kind of unsportsmanlike verbal taunting designed to put opponents off their game that has become common in the past couple of decades.
Among the famous examples that every cricket fan can quote are the mock question asked of Ian Botham as he arrived at the crease, “How’s your wife and my kids?”
The origin of the term isn’t obvious. Most dictionaries say, a little cautiously, that it derives from sledgehammer, based on the comment in the first known printed example, from World of Cricketing Monthly in 1977, that “The term comes from subtle as a sledgehammer”. Another school of thought holds it’s from the surname of Percy Sledge, an American soul singer who was popular with the Australian cricketers at the time and who was particularly famous for his hit of 1966 When A Man Loves A Woman. As so much sledging consists of sexual references, this is taken to be especially relevant.
These two origins are neatly conflated in the story told by the Australian spin bowler and commentator Kerry O’Keefe in his book According to Skull in 2004. He says it was coined in the early 1970s at a barbecue he attended with the teams from South Australia and New South Wales after a day’s play. One of the NSW players got out of line:
He made inappropriate comments to a lady and the fellow was ruled by John Benaud, our middle-order batsman, to be out of order. Benaud added that the transgressor’s outburst was as “subtle as a sledgehammer” and he momentarily became known as “Percy Sledgehammer” (a reference to the artist who belted out When A Man Loves A Woman). The “Percy” soon disappeared and for the remainder of the season anyone who used over the top language was known as a “sledge”.
Lexicographers are too sceptical a breed to take stories such as this at face value, despite the ear-witness testimony. But it does seem highly likely.
Incidentally, the first part of sledgehammer derives from an Old English source that is connected with the verb slay. So sledging is more appropriate than you might think.