It's well defined. It's been defined by the Supreme Court of Canada, by the Parker commission and by the Starr-Sharp report. Both the Parker commission in 1987 and the Starr-Sharp report in 1984 recommended that office-holders be required to sell their investments as the only way of getting rid of a financial conflict of interest. Also, both recommended that blind trusts should be prohibited because they were just a sham facade.
Their definitions.... It's essentially known for judges as reasonable apprehension of bias. For an apparent conflict of interest, a reasonable person who is reasonably well-informed would perceive that there is a conflict of interest.