Definitions of ruck:

• noun:   a crowd especially of ordinary or undistinguished persons or things

  Example: "His brilliance raised him above the ruck"

• noun:   an irregular fold in an otherwise even surface (as in cloth)
• verb:   become wrinkled or drawn together
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #16749)