IPA: /ˌɪndɪˈskrɛʃən/
KK: /ˌɪndɪˈskrɛʃən/
A lack of careful judgment or the ability to keep secrets, often leading to inappropriate or unwise actions or comments.
His indiscretion in sharing confidential information caused a lot of trouble for the team.
Indiscretion is formed from "in-" (meaning not) and "discretio" (from Latin, meaning separation or distinction). The word refers to a lack of discernment or the inability to separate right from wrong, leading to imprudent actions or remarks.
Think of 'not' ('in-') being able to make a 'distinction' ('discretio') — that's why indiscretion means a lack of good judgment.