faire l'école buissonnière

Etymology
Literally, "Make school (hidden) in bushes". Where the idiom comes from is quite unclear. There are three possibilities:

1) the idiom is related to the verb, and metaphorically going on an adventure in the forest among shrubs and bushes instead of attending school.

2) according to Swiss philologist and lexicographer, the idiom is related to and . In the 16th century, Lutheran priests struggled to preach the new religion in public. Thus, they started giving their teaching in the hinterland and in the woods (whence "").

3) according to French linguist and lexicographer, the idiom comes from the following sentence attributed to : « Vray est qu'elle fust buissonnière, l'escole de ceux de Pavie ». This sentence refers to prelates who in 1423 refused to attend the council of because of the plague that hit the city.

Verb

 * 1)  to play truant, to play hooky, to skip class, to ditch, to bunk, to mitch