One way to hold this word: a line marks the true amount, and someone's answer lands above it. Estimate is the answer; over- is the gap above the line. Everything the word does is that gap — sometimes the gap is in a number, sometimes in how highly you think of a person, and sometimes we name the too-high answer itself.
From the word’s history
Wiktionary gives the word simply as over- + estimate, with over- traced back through Middle English over-, Old English ofer- to a Proto-Indo-European form meaning 'above'. The modern picture and the parts still line up: the estimate goes above where it should stop.
來源字典把這個字拆得很乾脆：over- 加 estimate。over- 一路回推到中古英文 over-、古英文 ofer-，最早的意思就是「在…之上」。所以字的組成和今天的畫面是同一件事：估出來的答案停在該停的地方之上。
Wiktionary 'overestimate' etymology in the supplied packet (kaikki:3f6f69a190036ae4): 'From over- + estimate.'
登入就可以看每一支怎麼連回核心畫面。