Plague's relative resistance being overlooked (6)
I believe the answer is:
bother
'plague's' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bother that I've seen before include "Fuss; oh no!" , "Fuss, ado" , "Fuss and annoyance" , "Annoy, disturb" , "Pester, aggravate" .)