noun

1. Agent noun of stop, someone or something that stops something.

2. A type of knot at the end of a rope, to prevent it from unravelling.

   “Put a stopper in the knot.”

3. A bung or cork.

   “We need a stopper or the boat will sink.”

Synonyms: plug, local, stopping train

verb

1. To close a container by using a stopper.

   “He tightly stoppered the decanter, thinking the expensive liqueur had been evaporating.”