怠る
1
descuidar;desatender;olvidar
1
to neglect;to be negligent in;to be neglectful of;to fail to do;to leave undone;to avoid (doing);to shirk;to be unmindful of
あなたは「ありがとう」と言うことを怠った。
You neglected to say "Thank you."
2
to improve (of an illness);to get better