Congress parliamentarian Shantaram Naik on Thursday said union Home Minister Rajnath Singh should be sacked from the central cabinet as he had "violated oath of office by questioning insertion of 'secular' word in the Indian constitution"."Rajnath Singh has violated the oath of office by questioning in his speech in the Lok Sabha the insertion of 'secular' word in the constitution," Naik, Goa's lone Rajya Sabha member, said in a statement here.Rajnath Singh on Thursday said in parliament that "secular" was a most misused word and was only included in the constitution through the 42nd amendment. Having violated the oath of office blatantly, Singh has no right to remain in his post. Therefore, he deserves to be dismissed by the President of India, more so because he has given a fillip to unconstitutional views of those who have spread intolerance in the country," Naik said.