訳(わけ)あり(訳(わけ)あって)～ with reasons, Due to reasons, Defective, Problematic, Unique

訳(わけ)あり is a phrase that is often used before nouns to express that there is a reason for something being a certain way. The reason is normally complicated or something that the speaker does not want to or cannot explain. 訳(わけ)あり is literally made up of 訳(わけ), 'reason' or 'cause', and the continuative form (連用形(れんようけい)) of ある.

訳(わけ)あり will often be connected to nouns with の but sometimes it will be used like a な-adjective and be connected with な.

訳(わけ)あり can also be seen directly before some words, without な or の, however these are normally considered to be fixed expressions. This is often a way to euphemistically avoid giving negative descriptions of things.

Fun Fact

A closely related phrase is 訳(わけ)あって, meaning 'for a reason (which isn't specified)'. It is often used at the start of sentences when the speaker wants to say that there are some deeper reasons behind what they're saying, however they do not want to or cannot explicitly say what those reasons are. When not used in front of a noun, 訳(わけ)あり can also be used in a similar way.