Abarim Publications' online Biblical Hebrew Dictionary
The root-verb ארר ('arar) appears to originally have conveyed a binding, thwarting or restricting, and became applied in the sense of to curse someone; to bind them with a spell or hinder him with obstacles (Genesis 3:14, Exodus 22:28, Job 3:8). Note that the form and basic idea of this verb is also preserved in the verb ארה ('arah), meaning to gather.
Forty out of this verb's sixty-three occurrences are passive participles: ארור ('arur), one cursed or a cursed (person) (Genesis 3:14, Numbers 24:9, Deuteronomy 27:15).
This verb's only derivative is the feminine noun מארה (me'era), meaning a curse (Deuteronomy 28:20, Proverbs 3:33, Malachi 2:2).