IPA: /rɛˈtɪsənsi/
KK: /rɛˈtɪsənsi/
The quality of being reserved or not revealing one's thoughts or feelings easily.
Her reticency in sharing personal information made her seem mysterious to her colleagues.
Reticency → It is formed from "reticent" (from Latin "reticentem", meaning remaining silent or reserved) and the suffix "-cy" (meaning the state or condition of). The word "reticency" refers to the state of being reserved or inclined to keep one's thoughts and feelings to oneself.
Think of someone who is 'reserved' ('reticent') and how that describes their 'state' ('-cy') of not sharing much.