Risk is the degree of exposure to both negative events and their probable consequences.
Risk differs from uncertainty in that it can be measured.
Risk is measured in terms of both consequences and likelihood.
It is therefore pretty meaningless in discussion to say that there is a "risk" of death associate with an activity - unless the probability of that outcome is also stated.
Risk assessment is concerned with identifying the hazards associated with an activity, and also assessing the probabilities associated with each hazard - the sum of "hazard x probability" is effectively the overall risk.
From this a strategy of risk management can be implemented to mitigate the effects of the hazards and / or reduce the probabilities to lower the overall risk to an acceptable level, commensurate with the objectives (e.g. to go flying).
It may be that it is not possible to manage the risk to an acceptable level, in which case the sane decision would be not to embark on the endeavour!
Of course, the above is a great simplification of a complex subject! It is rarely easy to quantify all the hazards and associated consequences, let alone to calculate the probabilities. And I have not mentioned categorizing risk according to severity. Yet we do this daily at both conscious and unconscious levels for a wide variety of activities, from crossing the street to deciding whether the weather is suitable to go flying.
SD