New Delhi: From alluding to a party colleague as a "gangster's moll" to calling a Prime Minister a " nalayak" (useless person), the career diplomat in Mani Shankar Aiyar has allowed too many un-diplomatic gaffes to blot his political track record.

If Rahul Gandhi has now prodded him to apologise for his latest " neech kism ka aadmi (vile man)" barb at Narendra Modi, Aiyar had had to similarly eat crow after an attack on a previous NDA Prime Minister nearly two decades ago.

In November 1998, Aiyar, appointed Congress spokesperson, had dubbed Atal Bihari Vajpayee a " layak vyakti, nalayak neta (competent person, useless leader)".

"I have subsequently learned that the expression I used could have an un-parliamentary connotation," he said in his apology.

"Not being a native Hindi speaker, I seem to have inadvertently used an improper expression, for which I wish to tender my apologies to the Prime Minister for any offence unintentionally caused."

Aiyar had told this correspondent that he had initially been "tempted to use the Hindi word ayogya (undeserving), but in Tamil (Aiyar's mother tongue) it has a different and rather derogatory meaning".

So he consulted a dictionary and found there was a word, " nalayak", to describe a person as weak.

Aiyar had infamously dismissed Modi as a " chaiwalla" (tea seller) ahead of the 2014 Lok Sabha elections, allowing the BJP leader to portray the remark as an insult to his "humble roots" and project the Congress as arrogant.

"I promise you, in the 21st century, Narendra Modi will never become the Prime Minister of the country.... But if he wants to distribute tea here (at a Congress event), we will find a place for him," Aiyar had said.

It's not just political opponents who have felt the sting of Aiyar's verbal lashes.

In September 2013, he had described fellow Congress politician and Union sports minister Ajay Maken derisively as a "BA pass from Hansraj College" and wondered how he could use "big words like 'dichotomous'".

Aiyar's taunt reflected the scorn in which the brightest and the best from his alma mater, St Stephen's College, often regard their peers from not-so-posh institutions. So, students of the illustrious Hindu College are referred to as people from "across the road".

Kirorimal and Hansraj college may have impeccable academic credentials but their students do not figure on the Stephanian social radar, which restricts itself to the fellow "elite" from the upscale Miranda House and the Sri Ram College of Commerce.

In October this year, Aiyar had seemed to take a dig at, of all people, Sonia and Rahul Gandhi. Referring to the Congress organisational polls, he had said: "I feel that only two people can be the next Congress president, mother or son."

Congress insiders say that Aiyar is no longer close to either Sonia or Rahul and has not received an audience for months at either 10 Janpath, Sonia's home, or 12 Tughlaq Crescent, where Rahul lives.

On another occasion, he had referred to alleged 26/11 mastermind and internationally designated terrorist Hafiz Saeed with the honorific " sahab", angering the nationalist lobby.

"Hafiz Sahab belongs to a minority group; the majority of Pakistanis want peace with India," Aiyar had said.

When Arjun Singh, Sheila Dikshit and some others rebelled against then Prime Minister P.V. Narasimha Rao in 1995, Aiyar had alluded to Sheila as a "gangster's moll" in his magazine column.

Sometimes, though, his digs have sparkled with waspish wit. For instance, Aiyar once recalled noticing a remark by former Congress minister Natwar Singh on the visitors' book at St Stephen's.

"I am what I am because of St Stephen's," Natwar had written.

Aiyar asked for a pencil and scribbled under it: "Why blame the college?"