excuse(n.)和plea的区别？

excuse,理由；plea，借口。
excuse应该是中性词，若要强调理由不成立的话一般用bad excuse，虽然多用贬义但excuse本身并无褒贬；而plea本身就强调理由不成立，意为“借口”，贬义。
What a bad excuse,you'd better say it was just a plea.

excuse
1. 辩解[C][U]
2. 理由;借口[C][U]
There is no excuse for this chaotic state of affairs.
事情弄得如此之乱,已经没有什么理由可说了。
3. 原谅,饶恕[C]
4. 请假条[C]
I wrote an excuse for my absence from school.
我写了一张请假条,说明缺课的原因。
5. 歉意,道歉[P]

plea n.
1.请求,恳求[C][(+for)][+to-v]
The prisoner made a plea for mercy.
囚犯恳求宽恕。
2.借口,托辞[the S][(+of)][+that]
She left the party on the plea of a headache.
她借口头疼离开了晚会。
3.【律】抗辩,答辩[C][S1][(+of)]
He entered a plea of "not guilty" to the charges filed against him.
针对对他的指控他提出"无罪"的抗辩。

从词义上两者都有相通的意思,但后者更严重,倾向性更强吧

excuse me?

就怎么用的