i-adjective
vaguely fearful; apprehensive; gloomy about the future
Describes an uneasy, hard-to-pin-down dread or anxiety, often about something that hasn't happened yet. The fear is not sharp but lingering and indistinct.
将来のことを考えると空恐ろしくなる。
I feel vaguely fearful when I think about the future.
彼の冷静な態度がかえって空恐
His calm attitude was, on the contrary, somewhat alarming.