1 - Someone that cleans up the scraps in a field after a harvester finishes gathering the ripe fruits and vegetables.
2 - A term for someone who has to settle for the crap left over after the more privileged individuals pick through first.
"The harvester just finished with the field. Go send the gleaners to clean up."
"Last halloween my older brothers picked through my trick-or-treat bag and took all of my chocolate. All I had left were Smarties and raisins. I felt like a gleaner."
From the Wikipediadefinition: The HMSML Gleaner (H86) was the smallest commissioned vessel in the Royal Navy, at the time of her decommissioning, with a length of just under 15 metres.