From Longman Dictionary of Contemporary Englishsecurity guardseˈcurity ˌguard noun [countable] BOsomeone whose job is to guard money or a building
Examples from the Corpus
security guard• His extra two years had come about because he'd shot a security guard in the leg with a twelve-bore.• A security guard came to smile at our picnic on the grass.• The dark suited security guard glowered at him from within the bright interior of the shop.• Then he sneaked past the security guard without paying. 