( saying ) if you are going to be punished for doing sth wrong, whether it is a big or small thing, you may as well do the big thing
(YOU, ETC.) MAY / MIGHT AS WELL BE HANGED / HUNG FOR A SHEEP AS (FOR) A LAMB
Meaning of (YOU, ETC.) MAY / MIGHT AS WELL BE HANGED / HUNG FOR A SHEEP AS (FOR) A LAMB in English
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005