負責踢的那個人
-er 指人的那一半，畫面完全照字面走。
noun · B1
A player in a sports team whose job is to kick the ball, especially to score points. More widely, anyone who is doing the kicking.
（球隊裡的）踢球員
核心畫面
Start from the build: kick plus -er, the one that kicks. English uses -er for people and for things alike, so a kicker can be a person with a kicking job, or a part that gives something a sudden shove. Both keep the same picture — one short, sharp push that sends something somewhere it was not going a second ago.
先看組裝方式：kick（踢）加上 -er（做這件事的那個）。英文的 -er 可以指人，也可以指東西。所以 kicke…更多收起
先看組裝方式：kick（踢）加上 -er（做這件事的那個）。英文的 -er 可以指人，也可以指東西。所以 kicker 可以是隊上專門踢球的球員，也可以是機器裡把東西彈開的那個部件。兩邊共用同一個畫面：一下短而有力的推送，把某樣東西送到它一秒前還去不了的地方。抓住這一下，比記住一堆行業用法有用得多。From the word’s history
Wiktionary gives the form as kick + -er.
來源資料寫的是 kick 加 -er，也就是「踢的那一個」。
Wiktionary etymology_text in packet: From kick + -er (kaikki:3f6f69a190036ae4:968282302)
Two branches
最後補上的那一腳
同一下短而有力的推送，從球場搬到說話上：故事講完了，最後再補一腳。
noun · B2
The surprising detail that comes at the end of a story or situation and changes how you feel about the whole thing. It is often bad news, and it is usually the part the speaker has saved until last.
最後那個令人意外的關鍵