思し議ぎ

noun, noun or participle which takes 'suru'

conjecture; guess

Rare standalone use; modern Japanese almost exclusively uses this in the compound 不思議 (ふしぎ, 'mysterious'). The standalone noun or する-verb usage is literary or archaic.

• 「思し議ぎ」は現げん代だい語ごでは単たん独どくで使つかわれることは稀まれで、もっぱら「不ふ思し議ぎ」の形かたちで現あらわれる。

  In modern Japanese, 思議 is rarely used alone; it appears almost exclusively in the form 不思議.