In the sentence, "Commodus was a capricious ruler," what does "capricious" mean?

Capricious means reckless / unpredictable / tempermental

The definition of capricious means something or someone that is " given to sudden and unaccountable changes of mood or behavior." Unpredictable, inconstant. It's likely that Commodus was a ruler with sporadic and variable behavior. You never knew what he was gonna do or how he was gonna act.