¹ bump verb

• to hit (something, such as part of your body) against an object in a sudden and forceful way —often + against or on
• to hit and move (someone or something)
• to move into or against (someone or something) in a sudden and forceful way —often + up —sometimes used figuratively

² bump noun

• an area of skin that is raised because it was hit, injured, etc.
• a small raised area on a surface —often used figuratively in U.S. English
• an act of something hitting against something else