"""Be big of someone"" is an English idiom that means being generous, noble, or showing great character on someone's part. This phrase is typically used to praise someone who has acted generously or nobly, especially when they did not have to.

Unfortunately, this idiom doesn't have a direct Turkish equivalent, but the literal translation could be ""Birisinin büyük olması"". However, it's not often used in Turkish daily language. To express a similar sentiment in Turkish, you might say ""Birisinin büyüklüğünü göstermesi"" or ""Birisinin cömert ve asil davranması"". Both of these can be used to refer to someone showing generosity or acting nobly.

Detail explanation: 

""Be big of someone"" emphasizes the speaker's appreciation or admiration for the subject's actions. It's often used in situations where the subject has acted in a way that is selfless, generous, or morally correct, especially when it would have been easier or more advantageous for them to act otherwise. For example, if someone apologizes after making a mistake, someone might say ""It was big of them to apologize"". This way of using the idiom highlights the person's maturity, responsibility, and grace in handling a difficult situation. Similarly, if someone donated a large sum of money to a charitable cause, another person might comment ""It's big of you to donate that amount of money"". These kinds of phrases can collectively communicate the speaker's admiration, appreciation, and sometimes surprise about the magnanimity of the person in question."

"""Be big of someone"" is an idiomatic expression which means that someone is generous or has done something commendable or estimable. Below are 5 sentences with its translations:

1. ”It's very big of you to admit you were wrong and apologize.""
(Tabii ki hatalı olduğunu kabul edip özür dilediğin çok büyük bir davranış.)

2. ""It was big of John to step down and let George take the lead."" 
(John'un liderliği George'a bırakıp kenara çekilmesi gerçekten onurlu bir hareket.)

3. ”It's big of her to help her ex-boyfriend with his financial issues."" 
(Eski erkek arkadaşına maddi sorunlarında yardımcı olması ondan büyük bir davranış.)

4. ""It was big of Tom to give up his seat in the train for the elderly woman."" 
(Tom'un yaşlı kadın için tren koltuğunu vermesi çok büyük bir hareket.)

5. ”It was big of Sarah to donate her holiday bonus to charity.""
(Sarah'ın tatil bonusunu hayır kurumuna bağışlaması ondan yüce bir davranış.)"