What is meant by "actual" and "expected" according to the Malikis regarding the permissibility of combining Maghrib and Isha prayers due to rain?

The meaning of "waqi'" (actual) in the context of combining the two evening prayers due to rain is rain that is actually falling and descending at the time of Maghrib, in which case combining the prayers is permissible. As for "mutawaqqa'" (expected), its meaning is rain that is anticipated to fall soon, even if it has not yet descended. This is also one of the permissible reasons for combining prayers, but Al-Dusuqi said: If the prayers are combined in this situation and the rain does not materialize, then the second prayer should be re-offered within its time.