Wish magistrate to restrict dubious pronouncement for contest (4,4)
I believe the answer is:
long jump
'contest' is the definition.
(long jump is a kind of contest)
'wish magistrate to restrict dubious pronouncement' is the wordplay.
'wish' becomes 'long' (I've seen this in other clues).
'magistrate' becomes 'jp'.
'to restrict' means to remove the last letter (I've seen 'restricted' mean this (restricted can mean limited or reduced)).
'dubious pronouncement' becomes 'ump' (I am not sure about this - if you are sure you should believe this answer much more).
'jp' with its final letter removed is 'j'.
'long'+'j'+'ump'='LONG-JUMP'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for long jump that I've seen before include "Athletics event" , "Field event combining speed and agility" , "Sand-pit leap" , "Olympic field event in which Greg Rutherford won gold in 2012" .)