Allowing access to inside (4)

I believe the answer is:

open

(Other definitions for open that I've seen before include "'Frank, not secret (4)'" , "Ready for business; spread out; manifest" , "Candid and undisguised" , "See 12" , "Sports contest" .)

I've seen this clue in The Mirror.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.