Tongue-in-cheek is a term that refers to a style of humour in which things are said only half seriously, or in a subtly mocking way.

Origin of the term

The term first appeared in print in the book The Ingoldsby Legends by Richard Harris Barham, published in 1845. The author uses the term describing a Frenchman:

''He fell to admiring his friend's English watch.
''He examined the face,
''And the back of the case,
''And the young Lady's portrait there, done on enamel, he
''Saw by the likeness was one of the family;
''Cried 'Superbe! Magnifique!' (With his tongue in his cheek)
''Then he open'd the case, just to take a peep in it, and
''Seized the occasion to pop back the minute hand.

Tongue-in-cheek humour in fiction

Tongue-in-cheek humour in fiction often takes the form of gentle parodies. Such stories seem to abide by the conventions of an established serious genre, while in reality, they gently poke fun at some aspects of that genre. A tongue-in-cheek work still relies on these conventions and is not the same as a farce. Good examples of films that are made in a tongue-in-cheek way are An American Werewolf in London, Scream, or True Lies. Note that these films are still faithful to their genre (horror and spy, respectively) and are not out-and-out parodies such as Airplane!.

References

Humor | English idioms