Screen for Gladiator or The Guard (6)

I believe the answer is:

shield

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This might be a double definition.

'screen for gladiator' is the first definition.
'shield' can be an answer for 'screen' (synonyms). I am unsure of the 'for gladiator' bit.

'the guard' is the second definition.
(I've seen this in another clue)

'or' acts as a link.

Can you help me to learn more?

(Other definitions for shield that I've seen before include "Protect - prize" , "He slid (anag)" , "Protective cover" , "Piece of plated armour" , "Is held as protective device" .)

I've seen this clue in The Irish Times.

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