一いっ線せんを画かくする

expression, suru verb (special)

draw a line; make a distinction; distinguish

Used to emphasize a clear boundary or difference between two things, often in abstract contexts. The expression is idiomatic and typically used in formal or written language.

• 彼かれの作さく品ひんは他ほかの作さっ家かとは一いっ線せんを画かくしている。

  His work is clearly distinct from that of other writers.

• この政せい策さくは従じゅう来らいのものと一いっ線せんを画かくするものだ。

  This policy marks a departure from previous ones.