Anxiety, when taking off top to show boob (5)

I believe the answer is:

error

I'm a little stuck... Click here to teach me more about this clue!

'boob' is the definition.
(I've seen this before)

'anxiety when taking off top to' is the wordplay.
'anxiety when' becomes 'err' (I can't justify this - if you can you should believe this answer much more).
'taking off top' means to remove the first letter.
'to' becomes 'for'.
'for' with its first letter taken away is 'or'.
'err'+'or'='ERROR'

'show' is the link.

Can you help me to learn more?

(Other definitions for error that I've seen before include "Faulty judgment" , "1 down" , "Mistake, lapse" , "Howler" , "heresy" .)

I've seen this clue in The Guardian.

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.