Naughty child is playing around front of Ranby jail (8)
I believe the answer is:
imprison
'jail' is the definition.
(synonyms)
'naughty child is playing around front of ranby' is the wordplay.
'naughty child' becomes 'imp' (informal term for a misbehaving child).
'playing' becomes 'on' (on can mean playing or performing).
'around' indicates putting letters inside.
'front of' says to take the initial letters (the letter at the front of the word).
The initial letter of 'ranby' is 'r'.
'imp'+'is'+'on'='impison'
'impison' going around 'r' is 'IMPRISON'.
(Other definitions for imprison that I've seen before include "shut up" , "Detain" , "Put away" , "Send down" , "Put in gaol" .)