このましからざっちゃう
kono mashikara za' chau

Godan Verb (u)
Pre-noun Modifier

The completive aspect (contracted form) - indicates completion or regret of 好ましからざる

1. It's a bit complex, but here's a concise translation, acknowledging the nuance:; ; Wouldn't it have been better...; Too bad...; I regret...; If only...

Completed Action
Colloquial