noun
feeling of dread; sense of fear; awful feeling
Refers to a subjective, often lingering sense of fear or dread, not necessarily tied to an immediate threat.
暗い夜道を一人で歩くと、恐怖感に襲われる。
When I walk alone on a dark street at night, I am overcome by a feeling of dread.
彼は何の前触れもなく、突然強い恐怖感を覚
Without any warning, he suddenly felt an intense sense of fear.
不安感 is a feeling of anxiety or unease, often more vague and less intense than the dread implied by 恐怖感.
Compound of 恐怖 (きょうふ, 'fear') and 感 (かん, 'feeling, sensation').