The usage of bad words or filthy language in politics should be "strictly" banned to restore public confidence in politics and in their leaders, he told reporters here.

His remarks came when his attention was drawn to the recent jibe by Modi at Tharoor's wife Sunanda Pushkar.

"I disapprove of what Modi said about Tharoor's wife," Thakur said adding the Gujarat Chief Minister should have refrained from using such language.

In an apparent attack on Pushkar, Modi had said at an election rally in Shimla, "Wah kya girlfriend hai. Aapne kabhi dekha hai 50 crore ki girlfriend?" (What a girlfriend? Have you ever seen a 50-crore girlfriend).

Tharoor had later taken on Modi by tweeting, "My wife is worth a lot more than your imaginary 50 crores. She is priceless."

Thakur said there has been an explosion in the use of filthy and bad words by politicians against one another which was a matter of grave concern to one and all.

He said politicians should on their own refrain from using vulgar language against rivals to elevate the profession of politics and status of people in public life.

"Politics is not a bad profession per se, but the onus is on politicians to behave in a dignified manner and conduct themselves in a way that behoves their status and ensure that their profession remains healthy," he said.

Asked about his opinion on RSS ideologue S Gurumurthy's reported remark suggesting that BJP president Nitin Gadkari should not do business activities so long as he was the party chief, Thakur said it was not improper for a businessman or an industrialist to be in politics.

The decision should be left to Gadkari, he said but admitted it was a matter of propriety as far as he was concerned.

The BJP leader felt there was "ulterior motive" in the UPA government's proposal to dilute CAG by seeking to make it a multi-member body.

BJP, he said, would oppose tooth and nail the Centre's bid to compromise the independence and constitutional autonomy of the national auditor.