Made or became harsh, rough, or severe in a past tense; increased in harshness or severity.
From 'harshen' (the base verb form) plus the past tense '-ed' suffix. Follows standard English verb conjugation patterns for weak verbs.
This is a relatively uncommon past tense because most English speakers just use 'harsh' as an adjective, but when you need to show something becoming harsher over time, this word does the job perfectly.
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