The term 'unfavourable' is used to describe something that is DISADVANTAGEOUS, UNTOWARD, ADVERSE, or DISADVANTAGE. It is often used to refer to a situation or circumstance that is not beneficial or desirable. In other words, it is something that has a negative effect or outcome. Unfavourable can also be used to describe a person's opinion or attitude towards something, such as being unfavourable towards a particular policy or decision.