*-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'
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。
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☆
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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