Bring to bear (5)
'bring to bear' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for exert that I've seen before include "Bring into operation" , "Wield - apply" , "Bring to bear, perhaps influence" , "Apply (pressure)" , "Bring into play, wield" .)
'bring to bear' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for exercise that I've seen before include "Use" , "written school task" , "Practice session" , "Do it to get fit" , "Practice task" .)