Definitions of duck:

• noun:   small wild or domesticated web-footed broad-billed swimming bird usually having a depressed body and short legs
• noun:   a heavy cotton fabric of plain weave; used for clothing and tents
• noun:   flesh of a duck (domestic or wild)
• noun:   (cricket) a score of nothing by a batsman
• verb:   to move (the head or body) quickly downwards or away

  Example: "Before he could duck, another stone struck him"

• verb:   submerge or plunge suddenly
• verb:   avoid or try to avoid fulfilling, answering, or performing (duties, questions, or issues)
• verb:   dip into a liquid
• name:  A surname (rare: 1 in 50000 families; popularity rank in the U.S.: #5998)