Someone standing in a place where fear would be normal — a dark road, a high edge, a room full of people — and the fear simply is not switched on. The word is un- laid over afraid, so what you are really looking at is a missing feeling, and the sentence around it usually tells you what should have caused it.
The source gives the word as un- + afraid, so there is nothing hidden inside it: the core is the ordinary word afraid with the negative prefix laid on top.
來源資料寫的是 un- + afraid，所以這個字裡面沒有藏東西：核心就是 afraid 加上一個表示否定的 un-。
Wiktionary etymology supplied in this packet: "From un- + afraid." (source_ref kaikki:3f6f69a190036ae4:1085335473)
From the picture
敢去做：從不怕變成作風
同一個關掉的開關，往外走一步。既然沒有什麼攔住你，你就會去問、去做、去把話講出來，所以這個字從描寫情緒變成描寫一個人的作風。
adjective · B2
Willing to do something difficult, or to say something risky, because you feel sure you can handle what follows. It is used with 'to do something' or 'of doing something'.
敢於（做某事）
adjective · B2
Not frightened, in a situation where fear would be normal. It is often followed by 'of' to name the thing that does not frighten the person or animal.
不害怕的