bucko

From buck (“male antelope, deer, etc.; adventurous or high-spirited young man”) +‎ -o (colloquializing suffix).^[1]

• (Received Pronunciation) IPA^(key): /ˈbʌkəʊ/
• (General American) IPA^(key): /ˈbʌkoʊ/
• Rhymes: -ʌkəʊ

bucko (plural buckos or buckoes) (originally nautical slang, informal)

1. (also attributive) A boastful or bullying man.
   • 1983, Billy C. Lewis, “Doghole Schooners of the Redwood Coast”, in The Compass, page 24:

     A far cry from the miserable existance^{[sic – meaning existence]} of the common sailor brought about by bucko mates and bible preaching captains on the large ocean-going vessels, life aboard a doghole wasn't for everyone and losing your ship on the rocks or being rolled like a cork on a big wave chased many back to the open sea with an indelible meaning of the expression 'doghole' forever stamped in their minds.

   • 1997, Dan Yashinsky, Ghostwise: A Book of Midnight Stories, →ISBN, page 82:

     And the poor spailpin fanach running like the devil, his clothes tearing on briars and brambles, and his feet soaking and dirty water running out of his boots, and the three big buckos giving him every dirty look if he fustered or faltered, looks that'd sour milk or peel paint from walls.

2. Used as a term of address: young lad, friend, pal.
   • 2007, Howard [A.] Norman, Devotion, Boston, Mass.: Houghton Mifflin Company, →ISBN, page 90:

     He did an imitation of a pirate: "Arr, Arr, Arr, me buckos."

• Bouck