A stick with a spear on the end that you use to catch a fish by thrusting it down quickly into the fish is an example of a gaff.
When you stab and catch a fish using a stick with a spear on the end, this is an example of when you gaff the fish.
Knew that the carnival games had been gaffed.
We politely ignored his gaff.
We're going round to Mike's gaff later to watch the footie.
1916, Edgar Rice Burrows, Beyond Thirty (aka The Lost Continent), edition HTML, The Gutenberg Project, published 2008:"Numbers one, two, and five engines have broken down, sir," he called. "Shall we force the remaining three?" / "We can do nothing else," I bellowed into the transmitter. / "They won't stand the gaff, sir," he returned. / "Can you suggest a better plan?" I asked. / "No, sir," he replied. / "Then give them the gaff, lieutenant," I shouted back, and hung up the receiver.