Philistine's with a drink, exhausted, drained and unreal (8)
I believe the answer is:
imagined
'unreal' is the definition.
(similar in meaning)
'philistine's with a drink exhausted drained' is the wordplay.
'philistine's' becomes 'I'm' (where the crossword setter is 'Philistine').
'with' is a charade indicator (letters next to each other).
'a drink' becomes 'agin' (I can't justify this - if you can you should believe this answer much more).
'drained' means to remove the middle letters.
'exhausted' with its middle taken out is 'ed'.
'im'+'agin'+'ed'='IMAGINED'
'and' is the link.
(Other definitions for imagined that I've seen before include "Fancied" , "Dreamed" , "Created mentally" , "thought" , "Envisaged" .)