A clip (such as a hairpin, clothespin, paper clip); a clamp; a crab's pinchers, etc.
I really like the taste of crab pinchers.
To pinch or clamp s.t. between s.t.; to pin s.t; clip s.t. (as a paper clip clips paper, a clothespin pins clothes, or a hairpin pins hair).; to carry s.t. under one's arm.
Pin your wash up so it doesn't get blown away by the wind.