scavenger
noun
[ ˈskavɪn(d)ʒə ]
• an animal that feeds on carrion, dead plant material, or refuse.
• "carcasses are usually quickly disposed of by scavengers"
• a person who searches for and collects discarded items.
• "a reputation as a scavenger of discarded odds and ends"
• a person employed to clean the streets.
• a substance that reacts with and removes particular molecules, groups, etc.
• "4-aminosalicylic acid is not an effective free radical scavenger"
Origin:
mid 16th century: alteration of earlier scavager, from Anglo-Norman French scawager, from Old Northern French escauwer ‘inspect’, from Flemish scauwen ‘to show’. The term originally denoted an officer who collected scavage, a toll on foreign merchants' goods offered for sale in a town, later a person who kept the streets clean.
