Measure of restriction (5)
I believe the answer is:
chain
'measure of restriction' is the definition.
'chain' can be an answer for 'measure' (unit equal to 22 yards). I am not sure about the 'of restriction' bit.
'measure of restriction' is the wordplay.
'measure' becomes 'c' (C is an example).
'of restriction' becomes 'hain' (I can't explain this - if you can you should believe this answer much more).
'c'+'hain'='CHAIN'
Can you help me to learn more?
(Other definitions for chain that I've seen before include "Series of connected things" , "unwelcome to house seeker" , "Series of things linked together" , "Wickets so far apart in cricket" , "Tie" .)