Persons, male or female, who happen to interfere with someone else picking-up one of the opposite sex--the object. They can, but are not limited to, being salt if they really suck, or by flat out being a dork (which results in that dorkiness reflecting on you in an unfavorable manner), or they can be tactless and say something stupid that offends the object, or they can perhaps be a friend of a friend of a girlfriend--which could obviously be detrimental to the game in play. Example: I don't want Chris to come with us. He is nothing but salt. OR If perhaps your buddy walks up and says anything dumb while you are talking to a lady. After she is gone you can point to him, shake your head, and say, Salt, thereby referring to his salty behavior and calling him salt.
SALT
Meaning of SALT in English
Slang English vocab. Английский сленговый словарь. 2012