Omni- (all, everywhere, completely)
benevolent (
good,
loving)
Omnibenevolence is essentially being perfectly
good.
God is generally considered to be
omnibenevolent and
omnipotent which is often used as an argument against His existence: if there is evil, then
God can't be all good and all powerful at the same time.
See Omnibenevolence and Omnipotence for more related arguments.