Green’s Dictionary of Slang

aggressive, uncompromising.

1951		D. Dressler Parole Chief 143: He was incredibly naïve despite his tough-guy attitude.
1962		C. Perry Portrait of a Young Man Drowning (1963) 28: If they knew what a tough-guy big shot they are passing, they would shiver and shake.
1976		C. Keane Hunter 82: Even with all their tough-guy tactics [...] S.W.A.T. teams will not easily go to Watts.
1983		N. Heard House of Slammers 107: Jamison was in awe of his tough-guy reputation.
1985		E. Leonard Glitz 149: Slow husky voice with that South Philly street guinea accent, that tough-guy shit they learned when they were kids.
1999		Indep. Rev. 25 Aug. 1: The favourite tough-guy ticker is the Rolex Daytona.
2010		A. Steinberg Running the Books 114: An overeducated young brat who didn’t know the first thing about the real world of tough-guy prison combat.