Judge Crick briefly entertains it (6)
I believe the answer is:
critic
'judge' is the definition.
(I know that critic is a type of judge)
'crick briefly entertains it' is the wordplay.
'briefly' means to remove the last letter.
'entertains' indicates putting letters inside.
'crick' with its last letter taken off is 'cric'.
'cric' enclosing 'it' is 'CRITIC'.
(Other definitions for critic that I've seen before include "One who assesses" , "Judge of literary or artistic works" , "Performance judge" , "Writer of opinions on plays, concerts etc" , "Professional analyst of works of art" .)