Snake bites left two Europeans numb (6)
I believe the answer is:
asleep
'numb' is the definition.
(I've seen this before)
'snake bites left two europeans' is the wordplay.
'snake' becomes 'asp' (asp is a kind of snake).
'bites' indicates putting letters inside.
'left' becomes 'l' (common abbreviation).
'two europeans' becomes 'EE' (abbreviation for 'European' written twice).
'l'+'ee'='lee'
'asp' placed around 'lee' is 'ASLEEP'.
(Other definitions for asleep that I've seen before include "Napping" , "Please be at rest (6)." , "Resting unconscious" , "like a kipper" , "Snoozing" .)