John first out of bus route, leaving parking space (8)
I believe the answer is:
bathroom
'john' is the definition.
(synonyms)
'first out of bus route leaving parking space' is the wordplay.
'first out of bus' becomes 'b' (I can't explain this - if you can you should give a lot more credence to this answer).
'route' becomes 'path' (synonyms).
'leaving' suggests deleting specific letters.
'parking' becomes 'p' (abbreviation on road signs).
'space' becomes 'room' (enough space or room to do something).
'path' with 'p' taken out is 'ath'.
'b'+'ath'+'room'='BATHROOM'
Can you help me to learn more?
(Other definitions for bathroom that I've seen before include "place of 17 [WASHING]" , "Where to go" , "Abhor Tom (anag)" , "place for ablutions" , "WC" .)