Reasonable

An innocuous-looking adjective that nonetheless exercises the wits of attorneys the world over, especially when modified by the word "commercially".

As long ago as 1947 Lord Greene MR issued the seminal words on the topic in the famous case of AP Picture Houses v Wednesbury

See

• AP Picture Houses v Wednesbury (includes link to transcript)
• commercially reasonable manner
• Barclays v Unicredit