Restriction on moving vicious dog: not a lot (6)
I believe the answer is:
curfew
'restriction on moving' is the definition.
'curfew' can be an answer for 'restriction' (I've seen this before). I'm not certain of the 'on moving' bit.
'vicious dog not a lot' is the wordplay.
'vicious dog' becomes 'cur' (I've seen this before).
'not a lot' becomes 'few' (I've seen this in another clue).
'cur'+'few'='CURFEW'
Can you help me to learn more?
(Other definitions for curfew that I've seen before include "Hour to be home by" , "Nighttime limitation on movement" , "Restriction on going out" , "Early bedtime imposed by military" , "Night-time movement ban" .)