Have you ever had a brain fart and couldn't remember some common word or term that you needed to use? You can often get the point across by using whatever words might be close. That's how a peacock becomes a "disco chicken," or a cow can be called a "moo beast." In an AskReddit thread, people tell funny stories of folks communicating the best they can when the exact word escapes them.
Couldn't remember groomsmen, went with dudesmaids instead.
I forgot the word for ‘exterminator’ so I used ‘ant exorcist’ instead.
It gets even better when people who speak English as a second language go all the way around the world for an English term they don't know. That's how a reindeer became a "Christmas llama." That's really odd, but you still know what he means. And you'll always remember it. Read forty of the funniest incidents of this sort of thing at Bored Panda.