Snake given by important person to the queen (5)
I believe the answer is:
viper
'snake' is the definition.
(viper is a kind of snake)
'by important person to the queen' is the wordplay.
'by' says to put letters next to each other.
'important person' becomes 'vip' (VIP is an example).
'to the queen' becomes 'ER' (short for Elizabeth Regina ie Queen Elizabeth).
'vip' next to 'er' is 'VIPER'.
'given' acts as a link.
(Other definitions for viper that I've seen before include "A poisonous snake or treacherous person" , "Venomous snake, person" , "A small poisonous snake" , "Malicious person" , "spiteful person" .)