Goof

A goof is a mistake. The term is also used in a number of specific senses: in cinema, it is an error or oversight during production that is visible in the released version of the film.
Etymology.
Several origins have been proposed for the word. According to Merriam-Webster, "goof" is likely a variation of "goff" in an English dialect, meaning simpleton. Some say the word may come from an identically pronounced Hebrew word meaning "body", some even say it was just a mistake happened while typing the word "good", hence the word "goof" is also known as other word for mistake See the etymological explanation of Hessu Hopo, 'Goofy' in Finnish language.
The Spanish word "gofio" refers to the balls of toasted flour and salt eaten by the original inhabitants of the Canary Islands. In Latin America (esp. Cuba) the word "comegofio" (lit. "gofio-eater") came to refer to anyone from the Canaries, stereotyped as primitive or stupid.
Cinema.
In filmmaking, a "goof" is a mistake made during film production that finds its way into the final released picture. Depending upon the film and the actual scene, the goof may have different effects: a loss in realism, an annoyance, or it could just be funny. It is often a type of continuity error. Goofs are also known as "bloopers" or "mistakes".
There are several types of goofs, for example:
Goofs can be found in a large number of films and episodes, even in very expensive productions. The 1977 film "", for example, has been counted to have 200 goofs in it, ranging from disappearing props to a storm trooper hitting his head on an opening door.