This is the 6382nd most frequent Korean word.
않았다며
"Didn't do" or "saying that [someone] didn't do."
In this sentence, '않았다며' (saying that he hadn't/have not) is used to quote the reason provided by the subject in the saying form within the context of an excuse.
그는 어제 숙제를 하지 않았았다며 선생님에게 핑계를 댔다.
He made an excuse to the teacher saying that he hadn't done his homework yesterday.
Here, '않았다며' illustrates the subject conveying a subjective opinion or feeling as the reason for an action, quoted in spoken or indirect reported form.
그녀는 영화가 재미없었다며 극장을 일찍 나갔다.
She left the cinema early, saying that the movie was not interesting.
This usage of '않았다며' represents a quoting of a communicated believe by a collective subject in relation to their dissatisfaction.