IPA: /ˈædʒʊtənsɪ/
KK: /ædʒʌtənsɪ/
The position or role of being an assistant or helper, especially in a military context.
He was appointed to the adjutancy to assist the commanding officer.
Adjutancy is formed from "ad-" (meaning to or towards) and "juvare" (meaning to help). The word refers to the state of being in a position to assist or help, particularly in a supportive role.
Think of 'helping' ('juvare') someone 'towards' ('ad-') a goal — that's what adjutancy means.