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 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)
Two branches
闖進身體：侵犯與攻擊
這一支是把「闖進你的安寧」推到最實體的地步：闖進的不是你的時間或你的工作，而是你的身體。押上去的重量變成真正的身體侵犯，所以這一支的語氣最重，也是今天的主流用法。
verb · C1
To touch someone in a sexual way, or try to have sex with them, when they do not want it or cannot agree to it. It is used most often about an adult attacking a child, and it names a crime.
性侵；性騷擾
闖進安寧：打擾與妨礙（舊用法）
這一支離核心畫面最近，也最早：闖進來的不是身體接觸，而是你的清靜和你正在做的事。壓上去的重量是麻煩本身。今天口語幾乎不用了，但法規和舊書裡還活著。
verb · C2
To trouble or disturb someone, or to get in the way of what they are doing, so that they cannot carry on in peace. It can also cover touching or moving something that is not yours. This use is dated, and you now meet it mostly in older writing and in legal rules.
打擾；妨礙