The Definition of Bahirah and Sa'ibah
The names Bahirah, Sa'ibah, WasiIah and Hami are connected with customs prevailing during the days of Jahiliyyah. Commentators differ in their exegesis. It is possible that all these words were applied each to a different situation. We limit ourselves to the explanation given by Sayyidna Said ibn al-Musaiyyib ؓ as it appears in the Sahih of Al-Bukhari:
BAHIRAH, an animal the milk from which was dedicated in the name of idols, and was not used by anyone personally.
SA'IBAH, an animal which was released in the name of idols, like a bull in some rural areas of our time.
HAMI, a male camel having copulated with a particular number, which was also released in the name of idols.
WASILAH, a she-camel giving birth to female offspring continuously, uninterrupted by the birth of a male, was also released in the name of idols.
In addition to doing what was Shirk, these people were challenging the right of benefiting from the meat of an animal, or its milk, or riding it, declared permissible by Almighty Allah, and placing their own restrictions on their being lawful or unlawful - as if the office of making Divine laws belonged to them! And the cruel joke was that they took these polytheistic customs of theirs to be the source of attaining the pleasure and nearness of Almighty Allah. The answer to this was: Almighty Allah had never appointed these customs. If their elders did it, they fabricated lies against Him, and the ignorant masses accepted them. In short, a two-pronged warning has been given here by saying that the way it is a crime to invite hardships in Divine injunctions by asking purposeless questions, similarly, it is much more serious a crime that one goes about proposing things as Halal or حَرَام haram based on one's personal opinions and desires without the will and command of the Law-Giver. (Tafsir Usmani )