Resident of lair associated with eastern school on island (7)
I believe the answer is:
denizen
'resident' is the definition.
(I know that resident can be written as denizen)
'lair associated with eastern school on island' is the wordplay.
'lair' becomes 'den' (synonyms).
'associated with eastern school' becomes 'zen' (I can't explain this - if you can you should believe this answer much more).
'on' means one lot of letters go next to another.
'island' becomes 'i' (geographical abbreviation).
'zen' after 'i' is 'izen'.
'den'+'izen'='DENIZEN'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for denizen that I've seen before include "Inhabitant, occupant" , "Inhabitant (of the deep?)" , "Enid Zen (anag) - inhabitant of a particular place" , "Resident" , "Person in foreign country enjoying rights of natives" .)