You can think of bogey as the shape in the dark that you cannot name. Not a described monster with teeth and a colour — just something there, and the fact that you cannot see it well enough to say what it is. That gap is where all the fear sits, which is why the same word can move so easily out of children's stories. Give the gap to a worried adult and it becomes the thing hanging over the whole year. Give it to someone watching a radar screen and it becomes the dot with no name on it. Turn the light on, ask for the call sign, put the real numbers up — and in every case the bogey stops being one.
The packet's Wiktionary etymology says the origin is uncertain: probably related to bogle, or an alteration of Middle English bugge, a frightening spectre or scarecrow, with possible Welsh and Germanic connections. The source itself says uncertain, so this is a clue rather than a settled fact.
本批資料附的 Wiktionary 詞源說這個字來歷不確定：可能跟 bogle 有關，也可能是中古英文 bugge「嚇人的鬼影、稻草人」的變體，另外還提到威爾斯語和日耳曼語的可能性。資料本身就寫 uncertain，所以這裡只當線索看，不當定論。值得注意的是，它列出來的每一個可能來源都在講「嚇人的東西」，跟現在的核心畫面是同一個方向。
Wiktionary etymology text supplied in this packet (source_ref kaikki:3f6f69a190036ae4:494884570); the source explicitly marks the origin as uncertain
Four branches
黑暗裡的東西
最靠近核心畫面的一組：看不清楚、叫不出名字，所以可怕。一個活在故事裡，一個活在大人的煩惱裡。
noun · B2
A frightening imaginary creature — a ghost, goblin or monster of the kind children are told about, the sort that is said to hide in the dark. It is the same idea as a bogeyman.
妖怪、鬼怪（嚇小孩的那種）
高爾夫：那個看不見的對手
高爾夫這一支跟核心的接點，來源資料裡還留著：bogey 本來也指一個人下場時假想出來的對手。看不見、卻一直在跟你比——這正是核心畫面換了個場地。
noun · B2
In golf, a score of one shot more than par on a hole — that is, one shot worse than the number a good player is expected to need there.
（高爾夫）柏忌、高於標準桿一桿
雷達上沒有名字的點
核心畫面搬到螢幕上。看得到形狀、叫不出名字，所以要提高警覺——跟黑暗裡那個東西是同一種緊張。
noun · C1
An aircraft that appears on a radar screen and has not been identified. The people watching do not yet know whose plane it is, so they treat it as possibly unfriendly until they find out.
（雷達上的）不明機
鼻屎（另一條線）
這個意思跟「黑暗裡叫不出名字的東西」怎麼接上，本批資料沒有說明。與其硬編一個故事，這裡就把它當成另外一條線處理。
noun · B2
A small piece of dried mucus from inside your nose. The source marks it as informal and British English; American speakers usually say booger.
鼻屎