ENM is a more broad umbrella term, whereas polyamory is focused specifically on having multiple close romantic relationships (as I understand it, anyway). ENM also includes exclusively sexual relationships or other types of non-monogamy like relationship anarchy. So, polyamory is just a subset of ENM.
Non-ethical non-monogamy is generally just called "cheating" (or manipulation, or abuse) regardless of what the person perpetrating it calls it.
ENM is a more broad umbrella term, whereas polyamory is focused specifically on having multiple close romantic relationships (as I understand it, anyway). ENM also includes exclusively sexual relationships or other types of non-monogamy like relationship anarchy. So, polyamory is just a subset of ENM.
Non-ethical non-monogamy is generally just called "cheating" (or manipulation, or abuse) regardless of what the person perpetrating it calls it.