The Sporting News Record Book (1937) included this piece of baseball slang:
 
“Broadway—A flashy dresser, loud talker.”
 
“Broadway” is the name of a main thoroughfare in many cities. A person who can be described as “Broadway” is flashy and loud. The slang term is mostly of historical interest today.
 
     
OCLC WorldCat record 
The Sporting news record book.
Publisher: St. Louis, Mo. : C.C. Spink, 1908-1941.
 
OCLC WorldCat record 
Baseball guide and record book.
Publisher: St. Louis, Mo., Sporting News Pub. Co. [etc.] (1943 title.—ed.)
 
13 March 1937, Wilkes-Barre (PA) Record, “In This Corner with the Baseball Men,” pg. 20, col. 1L
Broadway—A flashy dresser, loud talker.
 
15 July 1937, Pottstown (PA) Mercury, “That’s My Story” by Don Rigg, pg. 11, col. 1:
BROADWAY—A flashy dresser, loud talker.
 
13 May 1941, The Daily Home News (New Brunswick, NJ), “Out on the Limb” by Gene Pinter, pg. 10, col. 1:
When we speak of Broadway we think of bright lights but it baseball it is a flashy dresser and a loud talker.
(From the Sporting News’ latest Record Book.—ed.)
 
Old Fulton NY Post Cards
21 April 1943, PM (New York, NY), “Ducks on the Pond” by Joe Cummiskey, pg. 27, col. 3:
Broadway—A flashy dresser, loud talker. Hiya, Leo!
(From Sporting News.—ed.)
 
24 June 1943, Miami (FL) Herald, “Spotlighting Sports” by Everett Clay, pg. 2B, col. 3:
Diamond Definitions—the vocabulary of words and phrases used to describe incidents, individuals and plays of baseball—is brought up to date in the 1943 Baseball Guide and Record Book.
(...)
Broadway—Flash dresser, loud talker.
   
12 August 1977, The Advocate (Newark, OH), “Worthy Notes” by Bob Worth, pg. 9, col. 3:
Broadway—A flashy dresser, loud talker.
(From the 1937 Sporting News Record Book.—ed.)
 
30 June 1990, San Diego (CA) Tribune, “Talkin’ baseball at the `orchard’ just isn’t the same” by Bud Maloney, pg. C-3:
In the days of minute baseball salaries, when players hardly were fashion plates, a “Broadway” was a flashy dresser or a loud talker, but woe be unto a “Broadway” who also was an “alibi Ike” and a “two-o’clock hitter.”