ichidan verb, transitive verb
arbitrarily decide; fix upon one-sidedly; jump to conclusions
Used when someone ignores another's position or evidence and unilaterally decides something is the case, often with a negative connotation.
彼は私の話を聞かずに、私が悪いと決め付けた。
He arbitrarily decided I was at fault without listening to my side.
まだ証
It's not good to jump to the conclusion that someone is the culprit without any evidence yet.
ichidan verb, transitive verb
scold; take to task; dress down
To strongly reprimand or accuse someone, often in a confrontational manner. Less common than sense 1.
上司はミスをした部下を厳しく決め付けた。
The boss harshly took the subordinate to task for the mistake.