She has a mirthfuller personality than her sister.

Her mirthsomeness was contagious, and everyone around her couldn't help but smile.

The children's laughter filled the room, creating a mirthsome atmosphere.

She became mirthier as the night went on.

She is the mirthiest person I know.

She had a mirthy laugh that filled the room with joy.

She is the mirthfullest person I know.

The mirthquakes shook the entire room with laughter.

The comedian's joke caused a mirthquake in the audience.