動詞 err:

1. to make a mistake or be incorrect
   同義詞：err, mistake, slip
2. wander from a direct course or at random
   同義詞：stray, err, drift

形容詞 erring:

1. capable of making an error
   同義詞：error-prone

1. Good students as they were (=Though they were good students), they sometimes erred.
   雖然他們是好學生，偶而也會犯錯。
2. She erred in failing to meet him in person.
   她錯在沒有親自與他見面。