cock of the walk

noun

1. the leader in a group, especially one with a conceited, domineering manner.

cock of the walk

noun

1. informal.
   a person who asserts himself in a strutting pompous way

Word History and Origins

Origin of cock of the walk¹

First recorded in 1850–55

Idioms and Phrases

A conceited, bossy person, as in Since his last promotion he's been acting like the cock of the walk—he's unbearable . This expression alludes to the rooster's proud strut about the barnyard, asserting his rule over hens and chicks. [Mid-1800s]