expression, i-adjective
not straightforward; hard to manage; tricky
Describes a person, situation, or problem that cannot be handled with simple or conventional methods; implies stubbornness, complexity, or unruliness.
See also: 一筋縄では行かない
彼は一筋縄でいかない相手だ。
He is a tough person to deal with.
この問題は一筋縄でいかない。
This problem is not easily solved.
Literally 'cannot be tied with a single rope', from 一筋縄 (one strand of rope) + でいかない (cannot go with). The idiom evokes the image of a person or thing that cannot be bound or controlled by ordinary means.