Coercion of the French on steamship (6)
I believe the answer is:
duress
'coercion' is the definition.
(thesaurus)
'of the french on steamship' is the wordplay.
'of the french' becomes 'du'.
'on' becomes 're' ('on' can be mean 'with reference to').
'steamship' becomes 'ss'.
'du'+'re'+'ss'='DURESS'
(Other definitions for duress that I've seen before include "Use of force or threats to get something" , "Constraint, force" , "Compulsion by use of force" , "Pressure applied by druses" , "Use of force or threats, often vile" .)