Definitions of bump:

• noun:   an impact (as from a collision)

  Example: "The bump threw him off the bicycle"

• noun:   a lump on the body caused by a blow
• noun:   something that bulges out or is protuberant or projects from a form
• verb:   knock against with force or violence

  Example: "My car bumped into the tree"

• verb:   dance erotically or dance with the pelvis thrust forward

  Example: "Bump and grind"

• verb:   assign to a lower position; reduce in rank
• verb:   remove or force from a position of dwelling previously occupied
• verb:   come upon, as if by accident; meet with
• name:  A surname (rare: 1 in 50000 families; popularity rank in the U.S.: #6982)