Maxipok is an term coined by Nick Bostrom to refer to a specific kind of risk strategy; just as maximax maximizes for reward and maximin targets the lowest-risk win, maxipok maximizes the probability of an okay outcome.
Maxipok is somewhat different from traditional decision theory measures, in that it does not assume a zero-sum game. Bostrom was originally using it to discuss the possible responses to existential risk -- asteroid strikes, supervolcanoes, hostile superintelligence, etc. -- which is essentially analyzing outcomes in terms of negative externalities. Because of this, maxipok generally has overtones of 'good for society' rather than 'good for me'. Because of the difficulty of correctly estimating future risk in general, and outside context problems specifically, maxipok is not a mathematically rigorously defined term. However, maxipok strategies tend to be cautious, forward-looking, robust, and flexible: they maximize future options, while minimizing future risk.
For those interested, the paper in which Bostrom introduced this term was Existential Risk Prevention as Global
Priority, Nick Bostrom, Global Policy Volume 4, Issue 1 (February 2013).