perish

perish /ˈperɪʃ/ verb
perishes; perished; perishing
perish
/ˈperɪʃ/
verb
perishes; perished; perishing
Britannica Dictionary definition of PERISH
[no object]
1 
formal + literary : to die or be killed
2 
formal : to disappear or be destroyed : to cease to exist
3 
British : 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