The principal of New York City’s first public school dedicated to the study of Arabic language and culture resigned under pressure yesterday, days after she was quoted defending the use of the word intifada as a T-shirt slogan. Debbie Almontaser, a veteran public school teacher, stepped down as the principal of Khalil Gibran International Academy, a middle school that is to open this fall in Brooklyn. This morning I tendered my resignation to Chancellor Klein, which he accepted, she said in a statement, referring to Schools Chancellor Joel I. Klein. I became convinced yesterday that this week’s headlines were endangering the viability of Khalil Gibran International Academy, even though I apologized. Those headlines had become impossible for Ms. Almontaser and the Department of Education to ignore. On Wednesday, a headline in The New York Post called Ms. Almontaser the Intifada Principal. Yesterday, an editorial in the paper had the headline, What’s Arabic for _Shut It Down’?