A gaff can be either one of two horrible sounding fishing implements, or a slang term for a person's home. Gaff can also mean a plan or secret, most often used in the phrase 'don't blow the gaff' which is similar to not letting the cat out of the bag. (English is fun, isn't it?)
Don't make the gaffe of adding an e - that's a different word.
Threave castle was once the gaff of Archibald the grim. (Upsetting him was way more than a gaffe)
I wonder if he used a gaff to catch fish in his moat?