What is the meaning of throwaway?

noun

• Sometimes offensive. ( a homeless boy who has been abandoned and roams the streets)
  • synonyms: street arab, gamin
• An advertisement (usually printed on a page or in a leaflet) intended for wide distribution.
  • usage: "he mailed the circular to all subscribers"
  • synonyms: circular, handbill, bill, broadside, broadsheet, flier, flyer
• Words spoken in a casual way with conscious under-emphasis.

adjective

• Thrown away.
  • usage: "wearing someone's cast-off clothes"; "throwaway children living on the streets"; "salvaged some thrown-away furniture"
  • synonyms: cast-off, discarded, thrown-away
• Intended to be thrown away after use.
  • usage: "throwaway diapers"