First to take one drink into examination (8)
I believe the answer is:
original
'first' is the definition.
('original' is associated in meaning with 'first')
'one drink into examination' is the wordplay.
'one' becomes 'i' (Roman numeral).
'drink' becomes 'gin' (gin is a kind of drink**).
'into' is an insertion indicator.
'examination' becomes 'oral' (oral is a kind of examination).
'i'+'gin'='igin'
'igin' inserted within 'oral' is 'ORIGINAL'.
'to take' acts as a link.
(Other definitions for original that I've seen before include "Native" , "Archetype, master copy" , "Archetype,master copy" , "First, earliest" , "- - sin" .)