*-If you say that someone is being unreasonable, you mean that they are behaving in a way that is not fair or sensible.
*-A complaint is a statement in which you express your dissatisfaction with a particular situation.
'unreasonable complaint'
Unreasonable complaintは「不当な苦情」という意味があります。 例えば、その苦情を言ってくる方が男性だとしましょう：
I've been having unreasonable complaints from that man quite often. で、「私はたびたび（quite often）あの男の人から不当な苦情を受けている」となり、その苦情は理屈に合わない苦情なんだと理解できます。
参考になれば幸いです☆
Groundless = not based on any good reason.
"Your fears are quite groundless."
Invalid = An invalid document, ticket, law, etc. is not legally or officially acceptable:
"I'm afraid your driving licence is invalid in Eastern Europe."
Unreasonable = beyond the limits of acceptability or fairness.
"An unreasonable request."
"Paul, what happened with that customer who was complaining about our service?"
"I investigated and it seems to be a groundless complaint. We supplied the item on time and in good condition."
"OK, good!"
Groundless = 根拠のない、不当な
"Your fears are quite groundless."
Invalid = 無効な書類、チケット、法、など公式、法律上認められない
"I'm afraid your driving licence is invalid in Eastern Europe."
Unreasonable = 正当性や容認できる度合いの限界を超えている様
"An unreasonable request." 不当な要求
例
"Paul, what happened with that customer who was complaining about our service?"
ポール、僕らのサービスについて文句をいっていたあの顧客はどうなったんだい？
"I investigated and it seems to be a groundless complaint. We supplied the item on time and in good condition."
全部調べてみましたけど、根も葉もない文句です。商品は時間通り、良好な状態で届いています。
"OK, good!"
わかった。いいね。
An unreasonable complaint can also be an:
Unfounded complaint
Unfounded means there is no evidence to support the complaint. It can mean it is exaggerated and taken out of context.
I hope that helps!
If a complaint is unreasonable it means it is unfair and unacceptable.
If a complaint is baseless it means it is not true and is not based on facts.
For example :
"The charges against her are baseless."
unreasonableはこの場合、不公平、容認できかねる、という意味になります。
baselessといえば、事実でない、事実に基づいてない、という意味になります。
例
"The charges against her are baseless."
彼女の逮捕の理由は事実に基づいていません。
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