unscrupulous

un- +‎ scrupulous

• IPA^(key): /ˌʌnˈskɹuːpjʊləs/
• Hyphenation: un‧scru‧pu‧lous

unscrupulous (comparative more unscrupulous, superlative most unscrupulous)

1. Without scruples; immoral.
   • 1888, Rutherford B. Hayes, edited by Charles Richard Williams, Diary and Letters of Rutherford Birchard Hayes, volume IV, Ohio State Archæological and Historical Society, published 1925, page 374:

     The real difficulty is with the vast wealth and power in the hands of the few and the unscrupulous who represent or control capital.

   • 2016, Doris L. Bergen, “Flashover: The Killing Centers, 1942-1944”, in War and Genocide: A Concise History of the Holocaust, page 272:

     Nazism, they wrote, had turned German youth into godless, shameless, unscrupulous murderers.

2. Contemptuous of what is right or honorable.

• scrupulous
• ethical
• upstanding