An unguarded gate.
An unguarded remark.
He listened to her unguarded thoughts.
There was an unguarded sweetness to her and her nervous chatter.
His principal fault was a want of tenacity and resolution; his tendency to unguarded language undoubtedly increased the number of his enemies.
Completely unguarded, her gray eyes were large and clear in the early morning light and her features relaxed.
Her walk was unguarded like her mannerisms, a sweet lack of refinement he wasn't sure he liked.