tall order

US /tɔl ˈɔr.dər/
UK /tɔl ˈɔr.dər/
"tall order" picture
1.

tâche difficile, demande exigeante

a request or task that is difficult to fulfill or achieve

:
Finishing this project by tomorrow is a tall order.
Terminer ce projet d'ici demain est une tâche difficile.
Asking him to change his mind now is a tall order.
Lui demander de changer d'avis maintenant est une tâche difficile.