Grievance leads to volcanic eruption by Jimmy (5)
I believe the answer is:
peeve
'grievance' is the definition.
(thesaurus)
'leads to volcanic eruption by jimmy' is the wordplay.
'leads to' indicates taking the first letters.
'by' says to put letters next to each other.
'jimmy' becomes 'pee' (I can't justify this - if you can you should give a lot more credence to this answer).
The first letters of 'volcanic eruption' is 've'.
've' put after 'pee' is 'PEEVE'.
Can you help me to learn more?
(Other definitions for peeve that I've seen before include "upset" , "cause irritation" , "grouse" , "Cause resentment" , "Intensely annoy" .)