What does this phrase mean the arrangement mightily displeased them?

The phrase "the arrangement mightily displeased them" means that the people involved were extremely unhappy with the way something was organized or decided. Here's a breakdown:

* Arrangement: This refers to a plan, agreement, or the way something is organized.

* Mightily: This is an adverb meaning "very" or "extremely."

* Displeased: This means to be unhappy or unsatisfied.

In essence, the phrase implies a strong and negative reaction to a particular arrangement.

For example:

* "The arrangement of the seating chart mightily displeased them, as they had hoped to sit together."

* "The new company policy mightily displeased the employees, who felt it was unfair."