It shall be unlawful for any person knowingly or willfully to resist, oppose or obstruct the Chief of Police, any police officer, the Municipal Judge or other municipal officers or employees in the discharge of their official duties; or, by threats or otherwise, to intimidate, or attempt to intimidate, any such officers or employees from the discharge of their official duties; or to assault, beat, revile, abuse, be disrespectful to or use abusive or indecent language toward or about, any such officers or employees, while such officers or employees are in the discharge of their official duties.