Learner's definition of PERISH
formal + literary
to die or be killed
to disappear or be destroyed
to cease to exist
to slowly break apart by a natural process
perish the thought
— used to say that you hope that something does not happen or to say that something will not happen
Who would take over as goalie if, perish the thought, he got injured?
What? Me help him out? Perish the thought.