Literal Translation
To do the greasy morning
Actual Meaning
To have a lie-in
Etymology
There are two hypotheses for this one:
Some point to the Latin adjective ‘crassus’ used to describe something (or someone) that is ‘thick’, ‘fat’ or ‘greasy’ by extension. The expression itself is thought to be derived from another 16th-century phrase, ‘dormir la grasse matinée’ which meant to stay ‘in the thickness of sleep’ for a long time.
The second explanation takes us back to a distant era when women proudly displayed their curves rather than hiding them shamefully. In the 17th century, it was said that upper-class women lazed around late in the morning to ‘faire du gras’ (put on weight), thus maintaining this aspect of the appearance.