It's unfriendly moving into Calais (10)
I believe the answer is:
antisocial
'it's unfriendly' is the definition.
I can't tell whether this defines the answer.
'moving into calais' is the wordplay.
'moving' indicates anagramming the letters (letters are moved around).
'into'+'calais'='intocalais'
'intocalais' with letters rearranged gives 'ANTISOCIAL'.
Can you help me to learn more?
(Other definitions for antisocial that I've seen before include "Disinclined to mix" , "Avoiding the company of others" , "withdrawn" , "Reluctant to mix" , "Disruptive to the community" .)