bucko

The term "bucko" is a slang formation that emerged in the late 19th century, primarily in nautical and later broader colloquial use. It derives from the English word "buck," which, since the 18th century, had been used to refer to a spirited, dashing, or fashionable young man, itself an allusion to the male deer. The appended suffix "-o" is a common feature in informal English and Australian slang, adding a tone of familiarity, address, or sometimes mild contempt. Thus, "bucko" literally constructs the sense of "a young buck, a fellow," carrying connotations of assertiveness or cheekiness, and its evolution exemplifies how colloquial speech creates new terms by combining existing lexical items with productive, mood-altering suffixes.

The word is a simplex formation from the English word "buck" (meaning a dashing young man or a male animal) with the addition of the informal, often familiar or derogatory, suffix "-o". The suffix "-o" is of uncertain but likely English or Australian English origin, used to form familiar or slang terms.