Grim, bishop caught by flash camera (7)
I believe the answer is:
macabre
'grim' is the definition.
(thesaurus)
'bishop caught by flash camera' is the wordplay.
'bishop' becomes 'b' (abbreviation used in chess).
'caught by' indicates putting letters inside.
'flash' is an anagram indicator.
'camera' with letters rearranged gives 'macare'.
'b' going within 'macare' is 'MACABRE'.
(Other definitions for macabre that I've seen before include "'Grisly, gruesome (7)'" , "Ghastly, gruesome" , "Gruesome, suggesting death" , "Chilling" , "'Grim, repellent (7)'" .)