Nigel Farage, leader of UKIP, denied that he was 'frit' for choosing not to stand in the forthcoming Newark byelection. Frit is a dialect or colloquial form of the past participle of the old verb to fright, nowadays superseded by to frighten. So, frit means frightened or scared.
Some journalists have noted that Mrs Thatcher used the term frit in the 1980s when she was prime minister. One of the best-known occasions was in April 1983 in the House of Commons. She was being taunted by the Labour Party a few weeks before the General Election of June 1983. In response to a question by Michael Foot, then leader of the Labour Opposition, and to an interjection by Dennis Healey, Foot's deputy, Thatcher retorted:
"The Right Honourable Gentleman is afraid of an election, is he? Afraid? Frightened? Frit? Could not take it? Cannot stand it?".
Frit seems to be in use in particular in Lincolnshire and in the Midlands. Mrs Thatcher may have been familiar with the word through having grown up in Grantham, Lincolnshire.