Rotten place restricted passport (6)
I believe the answer is:
putrid
'rotten' is the definition.
(synonyms)
'place restricted passport' is the wordplay.
'place' becomes 'put' (synonyms).
'restricted' becomes 'r' (this might be a standard abbreviation of which I'm unaware).
'passport' becomes 'id' (a passport is identification).
'put'+'r'+'id'='PUTRID'
Can you help me to learn more?
(Other definitions for putrid that I've seen before include "Turned" , "Foul" , "contaminated" , "High" , "Decomposing and fetid" .)