Loud blow to indicate the start of hostilities? (10)
I believe the answer is:
flashpoint
'start of hostilities?' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'loud blow to indicate' is the wordplay.
'loud' becomes 'f' (short for forte - 'loud' in music).
'blow' becomes 'lash' (lash is a kind of blow).
'to indicate' becomes 'point' ('point' can be a synonym of 'indicate').
'f'+'lash'+'point'='FLASHPOINT'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for flashpoint that I've seen before include "moment of emergency" , "Moment when hostility flares up" .)