害

Top roof radical (Kangxi #40) - pictures a peaked house roof with an extending eave. Indexes 害 in the building family with 家, 安, 守, 宿. The radical sets the scene: something happening inside or under a house. Many characters about danger and protection live here, since the home was the locus of safety.

Middle 丰 - historically the phonetic supplying an old reading close to gài/hài. 丰 itself depicts plants growing thickly. In 害 the upper-middle was originally a stylised stalks-on-soil shape that has since converged with the standalone 丰 in modern handwriting. Provides the sound.

Bottom mouth - pictograph of an open mouth. Carries the meaning core: the original sense was malicious speech, words spoken under one's roof that wound others. From 'speech that injures' came the broader 'to harm, to damage, danger.' The mouth-under-the-roof picture also fits 害怕 'to fear' - being afraid in one's own home.