Suitability

[nickelback]

What exactly does this mean when it comes to coaches? I can find anything where it is explained.

[MIJB#19]

From the in game help:

The Suitable category indicates how suitable a staff member is for a position in the current round. This is a 0-99 scale. Double-click on the entry to learn more about the staff member. During the draft, staff members who can't currently be selected will not show a suitable rating.

When looking for a defensive coordinator, the suitability score is modified with a bonus for defensive coordinators whose preferred defensive front matches your current front. This helps keep some continuity on your roster, as teams build rosters with players who fit specific roles.