weed

noun

• Any plant regarded as unwanted at the place where, and at the time when it is growing.

  "If it isn't in a straight line or marked with a label, it's a weed."

• Short for duckweed.
• Underbrush; low shrubs.
• A drug or the like made from the leaves of a plant.
• A weak horse, which is therefore unfit to breed from.
• A puny person; one who has little physical strength.
• Something unprofitable or troublesome; anything useless.