惧

Left-side heart radical - the indexing radical, side-form of 心. Files 惧 in the family of emotion verbs: 怕 fear, 恨 hate, 怀 cherish, 愁 worry, 悔 regret. Marks fear as an inner state of the heart, exactly how classical Chinese psychology categorized strong feelings.

Right 具 supplies the sound - jù exactly, no shift. Originally 具 depicted hands offering a cooking vessel - to furnish or possess. Pure phonetic role in 惧; the 'tool' meaning contributes little semantically. Same phonetic family: 俱 all, 飓 hurricane. The simplified 惧 replaces the bulkier traditional 懼 (with the 瞿 watchful-eye phonetic on the right).