Erum (ערום or Arum), (plural erumim ערומים) is a Hebrew word meaning "cautious, cunning, subtle, crafty, or prudent".
Erum is found many places in the Hebrew Bible some examples in:
Genesis 3:1 as erum, meaning "cunning", referring to the serpent or Satan (See note below).
Job 5:12 As erumim, meaning "cunning", referring to those who plot.
Job 5:13 As erum, meaning "shrewd", referring to tricksters.
Job 15:5 As erumim, meaning "clever", referring to well thought words.
Note: The consensus of the Biblical commentators in classical Judaism is that the "serpent" of the narrative in the Book of Genesis, was literally a serpent. They differ regarding what force it represented: The "evil inclination", "Satan", or the "Angel of Death". According to the Midrash, before this cunning beast was cursed, it stood erect and was endowed with some faculty of communication.