Arrest knight overwhelmed by bankruptcy (3,2)
I believe the answer is:
run in
'arrest' is the definition.
(thesaurus)
'knight overwhelmed by bankruptcy' is the wordplay.
'knight' becomes 'n' (chess).
'overwhelmed by' means one lot of letters goes inside another (I've seen this in other clues).
'bankruptcy' becomes 'ruin' (I've seen this before).
'n' inserted within 'ruin' is 'RUN-IN'.
(Other definitions for run in that I've seen before include "Disagreement, fight (colloq.)" , "Carefully bring to full working order - arrest" , "Brush" , "Prepare to deliver" , "drive new car" .)