Ah, the antonym of sentry is quite simple, my friend. Instead of a sentry watching over and protecting, the opposite would be someone who is unaware or neglectful of their surroundings. Just like how in a painting, you need both light and dark to create balance and harmony.
The possessive form of the noun sentry is sentry's.Example: After many hours, the sentry's feet were aching.
Sentry (GateKeeper)
sentry
Sentry Group was created in 1930.
Travel Sentry was created in 2003.
Sentry - Kree - was created in 1967.
Earth Sentry was created in 1999.
got it in axlom from a sentinel ... exactly opposite to entrance in the map (where the highest sloughter sentry mission takes place
The plural form of the word "sentry" is "sentries."
Try the link to Sentry.
Contact Sentry or a qualified locksmith.