In the UK and WASPier parts of Canada, ‘Esquire’ is just a polite way of saying ‘mister’ on an envelope. In the United States – for reasons which have never been entirely clear to us – it designates a lawyer (sorry, attorney), whether male or female.
It proved a problematic honorific for John Mark Heurlin, who held himself out as being entitled to practise law while suspended by the California state bar for serious misconduct. Heurlin described himself in correspondence and court filings as ‘John M. Heurlin, Esq.’, referred to himself as an attorney and had ‘Law Offices of John M. Heurlin’ on his letterhead. One of Heurlin’s arguments in his fourth round of discipline proceedings was that ‘the word “Esquire” has many meanings, including that of property owner and subscriber to the magazine Esquire’ (the decision doesn’t mention the Anglo- Canadian understanding of the word, supra). Epstein J of the state bar court didn’t buy Heurlin’s argument: In the Matter of John Mark Heurlin (case 09-O-10774, 7 August 2012). Huerlin’s intent was to mislead people as to his status and to practise when he couldn’t. Dude was disbarred.
[Link available here].