cock of the walk noun an important man in any given circumstance UK,1855 A fighting cock allows no other into its enclosure or “walk.”
Englishmen wear luxuriant mustaches, trick clothes, loud vests–sometimes monocles. Just conceited little cocks of the walk. — Lee Mortimer, WomenConfidential, p. 186, 1960
[T]he main man, the cock of the walk, the king of this particular little hill[.] — James Hawes, DeadLongEnough, p. 105, 2000