Abarim Publications' online Biblical Hebrew Dictionary
ארר
The 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 ('ara), meaning to gather.
There are several Hebrew verbs that may mean to curse but this one often occurs juxtaposed with the verb ברך (barak), meaning to bless (or rather to be or make free).
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).