Conflict is in fashion in this vessel? (7)
I believe the answer is:
warship
'vessel?' is the definition.
(warship is a kind of vessel)
'conflict is in fashion in this' is the wordplay.
'conflict' becomes 'war' (war is a kind of conflict).
'is in' becomes 'hip' (both can mean fashionable).
'fashion' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in this' is an insertion indicator.
'war'+'hip'='warhip'
'warhip' going around 's' is 'WARSHIP'.
Can you help me to learn more?
(Other definitions for warship that I've seen before include "Naval asset" , "Eg, destroyer, cruiser" , "Fighting vessel" , "Navy asset" , "frigate perhaps" .)