Important document graduate left (8)
I believe the answer is:
passport
'important document' is the definition.
'passport' can be an answer for 'document' (passport is a kind of document). I'm unsure of the 'important' bit.
'graduate left' is the wordplay.
'graduate' becomes 'pass' (pass the exam).
'left' becomes 'port' (left side of a ship - opposite of starboard).
'pass'+'port'='PASSPORT'
Can you help me to learn more?
(Other definitions for passport that I've seen before include "Official document required for foreign travel" , "Official document required for international travel" , "you might need Visa with this" , "Document facilitating travel" , "Traveller's ID" .)