Get knight covering king, giving check (6)
I believe the answer is:
screen
'check' is the definition.
(I know that screen is a more specific form of the action check)
'get knight covering king' is the wordplay.
'get' becomes 'see' (both can mean to understand).
'knight' becomes 'n' (chess abbreviation).
'covering' indicates putting letters inside.
'king' becomes 'CR' (short for Carolus Rex, King Charles in Latin).
'see'+'n'='seen'
'seen' enclosing 'cr' is 'SCREEN'.
'giving' acts as a link.
(Other definitions for screen that I've seen before include "Test or examine for the presence of disease or infection" , "Show a motion picture (of)" , "Block out" , "not to show? That's a riddle" , "Conceal or sift" .)