It's present on arrival (6)
I believe the answer is:
future
'it's present' is the definition.
(thesaurus)
'on arrival' is the wordplay.
I cannot quite understand how this works, but
'on' could be 're' ('on' can be mean 'with reference to') and 're' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for future that I've seen before include "Time that is 4 down" , "What's yet to come" , "Outlook" , "Time still to come" , "Verb tense; to come" .)