The Oxford Thesaurus An A-Z Dictionary of Synonyms - defence n.

1) shelter, protection, cover, guard, safeguard, shield: There is no defence against certain illnesses. 2) fortification, armour, barricade, screen, bulwark, rampart: Shore defences were set up, including barbed wire entanglements and concrete pillboxes. 3) excuse, apology, reason, apologia, explanation; justification, vindication, argument, plea, advocacy, support: His defence for decreasing welfare payments was inadequate. She spoke in defence of nationalizing industry.