In ice hockey and lacrosse, a player position with a primary responsibility to prevent the opposing team from scoring goals; same as defender in many other ballgames.(noun)
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Use "defenceman" in a sentence
"Sebastien Bourgon Huge (6-6) defenceman is gangly and awkward, hasn't grown into his body yet."
"Finnish defenceman is one of my personal favourites."
"This smallish Russian defenceman is one of my personal favourites."