material and substantial interference
Defined in 1 dictionary — Case Law
Definitions from Case Law
United States Supreme Court
where there is no finding and no showing that engaging in the forbidden conduct would 'materially and substantially interfere with the requirements of appropriate discipline in the operation of the school,' the prohibition cannot be sustained
Defined by the Supreme Court in - Tinker v. Des Moines Independent Community School District, 393 U.S. 503 (1969).