Bastardisation of "allow it", often used by youths who have been rude/outrageous and then wish to compound the effrontery by telling you to metaphorically "chill out".
Student : "Sir, you are well stink for making me learn this adding up crap."
Teacher : "There is no need for that bad language."
Student : "Lowit man!"
Teacher : "There is no need for that bad language."
Student : "Lowit man!"
by Teacherer July 11, 2008