Unsling v. t. (past & past part. unslung; pres. part. unslinging) (Naut.) To take off the slings of, as a yard, a cask, or the like; to release from the slings.
... already been advised to take all the rest you can at the halts. Unsling the knapsack, or take off your pack (unless you lie down upon it), and make yourself as comfortable as you can. Avoid sitting in a draught of air, or wherever it ... — How to Camp Out • John M. Gould
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