One way to picture molest: someone will not leave you in peace. A weight is pushed onto you and your quiet is broken into. In older English that push could be small — , blocking, getting in the way. Over time English kept the picture but narrowed what counts as the push, until the word came to mean breaking into a person's body itself.
From the word’s history
From Middle English molesten, from Old French molester, from Latin molestō 'to trouble, annoy', from molestus 'troublesome', from moles 'a burden, difficulty, trouble'. The burden in moles is the weight the word still puts on whoever it is used about.
從中古英文 molesten、古法文 molester，上溯拉丁文 molestō（使困擾），來自 molestus（麻煩的），再上溯 moles（重擔、難處）。那個「重擔」的意象，正好說明這個字為什麼從「煩人」一路走到「侵犯」：被 molest 的人，總是被壓上了不該有的重量。
Wiktionary entry for molest, etymology_text supplied in this packet (source_ref kaikki:3f6f69a190036ae4:792302237:19289)
登入就可以看每一支怎麼連回核心畫面。