Vladimir in play, say, wanting one drink (5)
I believe the answer is:
water
'drink' is the definition.
(water is an example)
'vladimir in play say wanting one' is the wordplay.
'vladimir in play say' becomes 'waiter' (Vladimir is a character in Waiting for Godot).
'wanting' suggests deleting specific letters (to want something can mean to lack it or need it).
'one' becomes 'i' (Roman numeral).
'waiter' with 'i' removed is 'WATER'.
(Other definitions for water that I've seen before include "One of the four classical elements" , "What makes the Somme" , "Inundate" , "Lake or river" , "Drink - type of 1 across" .)