oznaka cecha charakterystyczna in English:

They put their hallmark on every piece of furniture.

When Jimmy had gone, leaving the head, Smith went over it carefully, discovering certain hallmarks. Eventually he'd been able to trace it to an unlikely collaboration between two Zurich artisans...

Patient is the hallmark of a leader.

They also added that the incident 'did not bear the hallmarks of a terrorist attack

His hallmark isn't a punctuality.

Punctuality isn't his hallmark.