cowboy vs cattleman

cowboy and cattleman both are nouns.

Word	Noun	Adjective	Verb	Adverb
cowboy	Yes	No	No	No
cattleman	Yes	No	No	No

As nouns, cowboy and cattleman are synonyms defined as:

cowboy and cattleman: a male hired hand who tends cattle and performs other duties on horseback

Other synonyms of cowboy include cowman.

cowboy (noun)	cattleman (noun)
someone who is reckless or irresponsible (especially in driving vehicles)	a man who raises (or tends) cattle
a performer who gives exhibitions of riding and roping and bulldogging	a male hired hand who tends cattle and performs other duties on horseback
a male hired hand who tends cattle and performs other duties on horseback