Call about trouble, protesting strongly (7)
I believe the answer is:
railing
'protesting strongly' is the definition.
'railing' can be an answer for 'protesting' (to rail against something is to protest it). I am not sure about the 'strongly' bit.
'call about trouble' is the wordplay.
'call' becomes 'ring' (synonyms).
'about' means one lot of letters goes inside another.
'trouble' becomes 'ail' (synonyms).
'ring' going around 'ail' is 'RAILING'.
Can you help me to learn more?
(Other definitions for railing that I've seen before include "Haranguing -- horizontal bar on supports" , "Mocking" , "Iron barrier" , "Using abusive language" , "Fulminating against the barrier?" .)