A comical and slang term meant to denote "Maronites," who are an indigenous Christian people of Mount Lebanon. The connection with the two is that the founder of the Maronite sect, Mar Maroun (Saint Maron) has a name that somewhat rhymes with the band name Maroon 5. It is a word often used within a satirical context, yet in lighthearted manner, especially among English-speaking friends.
Hey Pierre, isn't that guy a Maroon 5?
Did you hear about the fight in the university? Must've been a bunch of Maroon 5's going at it again.