Reference to an underage man who appears to be a lot older than he actually is and who regularly attempts and succeeds in hitting on older women. The term originates from the lack of knowledge regarding the time at which Bosnia and Herzegovina gained its independence during the Yugoslav Wars and therefore, lack of knowledge regarding the age of the country.
How old do you think that guy is over there? Possibly Bosnian as he has an undefined jaw line.
Did you go Bosnian last night? Yeh and I felt like I was 21 again!