Meaning

To say something tongue-in-cheek means to say it in a deadpan joking way: you don’t intend your words to be taken at face value.

In an ironic manner, not meant to be taken seriously.

Origin

This phrase clearly alludes to the facial expression created by putting one’s tongue in one’s cheek. This induces a wink (go on – try it), which has long been an indication that what is being said is to be taken with a pinch of salt. It may have been used to suppress laughter. ‘Tongue in cheek’ is the antithesis of the later phrase – ‘with a straight face’.

The term first appeared in print in ‘The Fair Maid of Perth’, by that inveterate coiner of phrases, Sir Walter Scott, 1828:

“The fellow who gave this all-hail thrust his tongue in his cheek to some scapegraces like himself.”

It isn’t entirely clear that Scott was referring to the ironic use of the expression.

Cleverly amusing in tone.

In a bantering fashion.

Not seriously.