Fool around and Make merry

Fool around verb - To engage in attention-getting playful or boisterous behavior.

Make merry and fool around are semantically related In some cases you can use "Make merry" instead a verb "Fool around".

Make merry verb - Celebrate noisily, often indulging in drinking; engage in uproarious festivities.

Fool around and make merry are semantically related in celebrate topic. Sometimes you can use "Fool around" instead a verb phrase "Make merry", if it concerns topics such as revel, have fun.