Ruthless (3-3-3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ruthless</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for dog-eat-dog that I've seen before include "Ruthless competition of canine cannibals" , "Internecine competition" , "Savagely ruthless" , "Ruthless competition - savage self-concern" , "Ruthless competition like canine cannibalism" .)
(Other definitions for hard-nosed that I've seen before include "Realistic and tough-minded" , "Tough and uncompromising" , "Unsentimental, shrewd" .)