In tanning area, drop cap and loosen tie (7)

I believe the answer is:

unstrap

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

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

I can't explain the remainder of the clue.

(Other definitions for unstrap that I've seen before include "Remove fastenings from" , "Release" , "loose" , "Loosen tie" .)

I've seen this clue in The Times and The Sunday Times.

Want a hint initially instead of a full solution? Install my app