Uninformed. Ignorant of the situation. Not receiving appropriate information. Think of "the loop" as being a communications channel, and therefore being out of the loop means no one is communicating with you to get you the information you need.
Synonyms for out of the loop
On this page, you will find 30 slang terms related to out of the loop. Some of the top words include: hard headed, smupid, PICK UP, Stormz, pookies, and 25 more.