Which word describes something that occurs by happy chance?

The word "fortuitous" refers to something that happens by accident or chance, particularly in a way that is favorable or beneficial. It conveys a sense of happy coincidence or a fortunate occurrence that comes about unexpectedly. In various contexts, it might describe events that lead to positive outcomes purely by chance, such as stumbling upon a great opportunity or a serendipitous meeting.

Other options do not convey this meaning. For instance, "indifferent" refers to a lack of interest or concern, which is unrelated to the idea of a happy chance. "Inured" means to be accustomed to something, typically something unpleasant, and does not relate to chance or fortune. "Frugality" pertains to the quality of being economical or restraint with resources, which also diverges from the concept of something occurring by happy chance.