This phrase means that a person is lacking in intelligence, not through any form of retardation but a lack of trying.
Brittney: "What is an Intelligence Quotient?"
Teacher: "You mean an IQ, the thing we have been discussing for the last 10 minutes."
Friend of Brittney: "Seems like your lacking number 4."
Teacher: "You mean an IQ, the thing we have been discussing for the last 10 minutes."
Friend of Brittney: "Seems like your lacking number 4."
by Andres Gonzalez February 8, 2008