comme il faut (kohm-eel-FOE) adj. in accordance with accepted standards or conventions; socially acceptable; in keeping with customs or propriety; proper.
This phrase is derived from the French words comme ("like, as") and il faut ("it is necessary"), and is one of those foreign expressions I have difficulty keeping straight in my head. My French is spotty, as I am self-taught in the Gallic tongue, and French idioms are one of my weakest points, due in no small part that I speak the language poorly and rarely use it.
I came across the phrase today in a book on the Prussian king Frederick the Great, in which the free-spirited crown prince mused about his 1732 assignment by his father (Frederick William I) to a military post in Neuruppin:
We drill here comme il faut, new brooms must sweep clean, and I must justify my rank and demonstrate that I am an 'efficient officer.'