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Icebreaker: noun - something that breaks up moving ice to diminish its impact, especially a device protecting the upstream end of a bridge pier; ship designed to break a channel through ice; something that eases tensions in a social gathering.
'Unexpected falls in the temperature had caused the sea ice to form more rapidly than usual and the explorers were forced into calling for an icebreaker to rescue their vessel from disaster as the ice sheet closed around them.'
'"What we need here is an icebreaker." Shirley said, as she stepped onto the table and began to remove her clothes, one by one.'