Pros in sort of jail (6)
I believe the answer is:
prison
'jail' is the definition.
(I know that jail can be written as prison)
'pros in sort' is the wordplay.
'sort' indicates an anagram.
'pros'+'in'='prosin'
'prosin' anagrammed gives 'PRISON'.
'of' acts as a link.
(Other definitions for prison that I've seen before include "Stir - can" , "Nick" , "Correctional institution" , "Wormwood Scrubs, for example" , "Slammer" .)