Definitions of smooth:

• noun:   the act of smoothing

  Example: "He gave his hair a quick smooth"

• verb:   free from obstructions

  Example: "Smooth the way towards peace negociations"

• verb:   make smooth or smoother, as if by rubbing

  Example: "Smooth the surface of the wood"

• verb:   (of surfaces) make shine
• adjective:   having a surface free from roughness or bumps or ridges or irregularities

  Example: "Smooth skin"

• adjective:   of the margin of a leaf shape; not broken up into teeth
• adjective:   lacking obstructions or difficulties

  Example: "The bill's path through the legislature was smooth and orderly"

• adjective:   not marked with wrinkles
• adjective:   without breaks between notes; smooth and connected
• adjective:   without chinks or crannies
• adjective:   smoothly agreeable and courteous with a degree of sophistication

  Example: "The manager pacified the customer with a smooth apology for the error"

• adjective:   smooth and unconstrained in movement

  Example: "A long, smooth stride"