BIL
BIL has 2 meanings
Brother-in-law
BIL is an acronym that stands for "brother-in-law" and is typically used in text messages, emails, and chatrooms. The acronym refers to the brother of a partner's spouse or husband of a sibling.
MIL, FIL, and DILare used to refer to "parent-in-law" relations. And SIL is used for "sister-in-law" or "son-in-law".
Example
I get along with my BIL pretty well
Can you score under par in this golf terms quiz?
BIL is an acronym used to notify the recipient that his or her boss is listening or watching the chat session. It is similar to the PAW and POMS acronyms.
Since the work environment is not the most appropriate place to talk about personal or offensive employees have to be covert about their conversation content. The acronym allows the sender to discreetly tell the recipient to be careful what he types in a way that the boss wouldn't notice.