1.Nouna period of time in which a holy person (someone believed to be potentially on their way to sainthood) experiences a seeming withdrawal of God's previously-felt presence in their lives, and undergoes stark spiritual attacks. This period of time is seen (by Catholics) to be a period in which God is calling the holy person to rid themselves of any remaining vestiges of self-pride and vanity that they may have.
"Your dear friend ought to take heart. From what you have told me, it is quite likely that they are going through a dark night of the soul."