to label someone or something; to attach a (often simplistic or negative) label or stereotype that fixes perception of them.
メディアが彼に犯罪者のレッテルを貼ると、回復は難しい。
If the media labels him a criminal, it will be difficult for him to recover his reputation.
人を一度レッテルを貼って判断するのはよくない。
It's not good to judge someone by sticking a label on them once.
自分にネガティブなレッテルを貼らないように意識している。
I'm careful not to put negative labels on myself.