likely
chance
Not necessarily. In that the word means "by chance or by accident," I suppose it could describe a robbery that occurred by that means, HOWEVER, in common usage the word "fortuitous" is usually associated with GOOD things happening to someone.
Serendipty
"Chance" fundamentally can be either a noun or a verb, and the noun is often used as a "substantive adjective", as in the phrase "chance encounters".
What are the chances of that happening? Its either luck, or chance.
The root word for chance is "cadere," which is Latin for "to fall." This reflects the idea of something happening by random or unpredictable circumstances.
The noun 'luck' is an uncountable, common, abstract noun; a word for chance happening of fortunate or adverse events; the accidental way events occur; a word for good fortune; a word for a concept.
Inevitable
prevent
intermittent
It is something you do that you are not sure about the outcome. Another word would be gamble or risk.
Prevention means to keep something from happening.