The word "不知所措" is formed through the sequential combination of four characters: 不 (not) negates 知 (to know) creating "不知" (do not know), while 所 (a particle that nominalizes the following verb) is attached to 措 (to handle) forming "所措" (what to do), resulting in the literal meaning "do not know what to do", which expresses a state of bewilderment.