Fancy legal centre sues delinquent (5)
I believe the answer is:
guess
'fancy' is the definition.
(I've seen this before)
'legal centre sues delinquent' is the wordplay.
'centre' indicates the central letters.
'delinquent' indicates an anagram (a suspicious or criminal version of the letters).
The central letter of 'legal' is 'g'.
'sues' with letters rearranged gives 'uess'.
'g'+'uess'='GUESS'
(Other definitions for guess that I've seen before include "Estimate on the basis of little information" , "Speculate" , "Take a stab at the answer" , "Imagine" , "Estimate; suppose" .)