  | רע | ra |
The Hebrew word for a friend is רע (ra, Strong's #7453). This word can also mean a "companion," and is related to many words that have to do with shepherding and the shepherd, the companion and friend of the flock. The verb רעה (R.Ah.H, Strong's #7462) means "to feed," but the participle form of this verb, רעי (ro'iy) is a shepherd. The words מרעה (mir'eh, Strong's #4829), מרעית (mar'iyt, Strong's #4830) and רעי (r'iy, Strong's #7471) mean "pasture."
Interestingly, the word רע (ra, Strong's #7451) can also mean "bad" or "evil." How can this one word mean both "friend" and "evil?" While the Modern Hebrew alphabet consists of twenty-two letters, evidence suggests that there were additional letters in the original Semitic and Hebrew alphabets. One of the ancient Semitic languages of Canaan was Ugarit. This ancient language is almost identical to the Hebrew language of the Bible but, instead of consisting of twenty-two letters it has twenty-eight letters. One of the major differences between Ugarit and Hebrew is the additional letter ghayin, which does not exist in Hebrew, but evidence suggests that the letter ghayin did originally exist in the Ancient Hebrew alphabet, but at some point in the past, prior to the writing of the Bible, the letter ghayin began to be written with the letter ayin.
Therefore, The Hebrew word רע (ra, Strong's #7451), meaning "evil," was originally spelled resh-ghayin, whereas, the Hebrew word רע (ra, Strong's #7453), meaning "friend," was originally spelled resh-ayin.