coercion n.

early 15c., cohercioun, "compulsion, forcible constraint," from Old French cohercion (Modern French coercion), from Medieval Latin coercionem, from Latin coerctionem, earlier coercitionem, noun of action from past-participle stem of coercere "to control, restrain" (see coerce).

It defies the usual pattern where Middle English -cion reverts to Latin type and becomes -tion. Specific sense in reference to government by force, ostensibly to suppress disorder, emerged from 19c. British policies in Ireland. "As the word has had, in later times, a bad flavour, suggesting the application of force as a remedy, or its employment against the general sense of the community, it is now usually avoided by those who approve of the action in question" [OED].