Person radical on the left - the side-form of 人, indexing 傻 as a description of a human trait. Same radical anchors 傻 alongside 你, 他, 们, 体, 仙 - the family of human-state characters. Here it tags "foolish" as a quality of a person rather than a thing.
Top-right 囟 - depicts the soft spot on a baby's skull, the unhardened crown of the head. Inside 傻 it stands for an undeveloped, infantile mind: the brain still soft and unformed. A vivid mnemonic for "simple-headed, foolish."
Middle-right 八 - two short strokes splaying outward, ancient symbol of dividing or scattering. Below the soft skull above, it suggests thoughts spreading every which way without focus. Adds the "scatter-brained" nuance to 傻.
Bottom-right 夂 - a downward foot, the trailing-step radical seen in 冬, 处, 各. Here it pictures someone walking aimlessly, plodding along. The full right side stacks soft-skull + scattered + slow-foot = the prototypical "simpleton walking around in a daze."
