It wasn't exactly the sort of response he usually gets after a big show.

After 50 Cent headlined a music festival in the Caribbean island nation of St. Kitts and Nevis on June 25, local police arrested the rapper -- for uttering a particular bit of profanity during his set!

TMZ reports that cops jailed Fiddy after he used the word "mother-----" -- which is apparently illegal there -- during his concert.

In a fan-posted Instagram video, the rapper can be heard using the curse word while performing his song "P.I.M.P." in front of a crowd of 40,000 people.

#50cent #PIMP #stkitts #stkittsmusicvestifle

A post shared by Samantha Stowe (@yayysamm) on

Sources told TMZ that 50 Cent had been warned not to use profanity during his concert. But his DJ didn't have a clean version of the rapper's set -- plus Fiddy failed to pull the mic away when he said the offending word.

Afterward, he was booked for using profanity in public. Although it's a minor offense -- reports that the rapper's bail was less than $400 -- he still has to stay put in St. Kitts and Nevis until the courts reopen on June 27, at which time he'll be required to pay a fine for his crime.

It's not the first time the island nation has punished a rapper for using foul language during a concert there: The same thing happened to DMX when he performed at the music festival in 2003.