A tough, difficult, or stubborn person; someone who is hard to deal with or resistant to change.
From 'hard' (Old English) combined with 'case' (from Old French 'casse'), originally meaning a difficult legal case, extended to difficult people.
The term 'hardcase' became popularized in military slang to describe soldiers who were unflinching or couldn't be intimidated—it eventually generalized to describe any tough, inflexible person.
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