A person who is the embodiment of garbage. One who posses the physical qualities of garbage. Not one in sanitation, but someone who is garbage. An adjective used as a noun.
Ben: Wow , Mike is being total garbage right now.
Ryan: Ya, he is a Gerund!!
The gerund is the verb form ending in -ing which acts as a noun. The one word riposte "Gerund" by some self-satisfyingly smug pedant indicates an abuse in its usage. It often muddies the intended meaning, and makes one want to lamp the complainant.
We a-walking to school. Reminiscent of Shakespeare's stylistic poetry.
(Extract from an Appalachian English song)
On the Seventh day of Christmas, my true love sent to me. Seven swans a-swimming, six geese a-laying.
(Extract from a nursery rhyme ca. 1905)
I saw the ship a-sailing, a-sailing on the sea, and oh!It was all laden, with pretty things for thee!
Influenced modern day Patois slang.
This usage fell into disuse in modern English and is now regional or dialectal. A similarity in usage can be noted in the European Portuguese language structure.