Sister at first by herself almost in the hairdresser’s? (5)
I believe the answer is:
salon
'the hairdresser's?' is the definition.
(I've seen this before)
'sister at first by herself almost' is the wordplay.
'at first' says to take the initial letters.
'by herself' becomes 'alone'.
'almost' means to remove the last letter (most of the word but not all of it).
The first letter of 'sister' is 's'.
'alone' with its last letter taken off is 'alon'.
's'+'alon'='SALON'
'in' is the link.
(Other definitions for salon that I've seen before include "social event" , "Loans for elegant guest room" , "Elegant reception room" , "Large reception room" , "Formal sitting room" .)