Drink litres -- our getting drunk without measure of intelligence? (6)
I believe the answer is:
'drink' is the definition.
(liquor is a kind of drink)
'litres our getting drunk without measure of intelligence?' is the wordplay.
'litres' becomes 'L' (abbreviation).
'getting drunk' indicates anagramming the letters.
'without' indicates putting letters inside ('without' can be similar in meaning to 'outside').
'measure of intelligence?' becomes 'IQ'.
'our' with letters rearranged gives 'uor'.
'uor' enclosing 'iq' is 'iquor'.
(Other definitions for liquor that I've seen before include "Alcoholic beverage" , "Strong alcoholic drink" , "Any alcholic drink" , "Any alcoholic drink made from distillation" , "Alcoholic drink, booze" .)