Legal officer has trouble breaking strike (7)
I believe the answer is:
bailiff
'legal officer' is the definition.
(someone who enforces the law)
'trouble breaking strike' is the wordplay.
'trouble' becomes 'ail' (synonyms).
'breaking' means one lot of letters goes inside another.
'strike' becomes 'biff' (I've seen this in other clues).
'ail' placed within 'biff' is 'BAILIFF'.
'has' is the link.
(Other definitions for bailiff that I've seen before include "Law officer who helps sheriff, say to foreclose" , "Landlord's agent or steward" , "Landowner's agent" , "Sheriff's officer - landlord's agent" , "Court official" .)