壁越し推量

(1)a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence); "speculations about the outcome of the election"; "he dismissed it as mere conjecture"

(2)推測や推量で形成された仮説（普通はっきりとした証拠がない）

(3)an estimate based on little or no information

(4)わずかな情報あるいは全く情報がない状態での推測