THE ALPHABET GAME (O)

Hello readers and Alphabet Game participants! Welcome back. Are you ready for today's challenge? We look forward to your answers. 

Here is today's sentence. Its missing word begins with the letter O: 

Sentence: I lost my key and now I am locked o_____. 

Hint 1: This is a part of a phrasal verb.

Hint 2: It means "to close a place in order to stop someone from getting in."

Give us your answer on one of our social media sites (Facebook or Twitter) and we will provide the correct answer later. We will also include the answer in the next Daily Vitamin email. 

Thank you!