From Longman Dictionary of Contemporary Englishthe unacknowledged leader/authority etcthe unacknowledged leader/authority etcSTHINK/HAVE THE OPINION THATsomeone who is a leader etc but who has not publicly or officially been given that position → unacknowledged
Examples from the Corpus
the unacknowledged leader/authority etc• In the hierarchy of Balniddrie-although pecking-order might be a more accurate term-Kara was the unacknowledged leader. 